Network Working Group Murtaza S.Independent Submission M. ChibaInternet-Draft AlexanderRequest for Comments: 6812 A. ClemmIntended status:Category: InformationalStevenS. MedleyExpires: April 22, 2013 JosephISSN: 2070-1721 J. SaloweySudhirS. ThombareEshwarE. Yedavalli Cisco SystemsOctober 19, 2012January 2013 CiscoService LevelService-Level Assurance Protocoldraft-cisco-sla-protocol-04Abstract Cisco'sService LevelService-Level Assurance Protocol (Cisco's SLA Protocol) is a Performance Measurement protocol that has been widely deployed. The protocol is used to measureservice levelservice-level parameters such as network latency, delay variation, and packet/frame loss. Thisdraftdocument describes the Cisco SLA ProtocolUDP measurement typeMeasurement-Type UDP-Measurement, to enable vendor interoperability.Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].Status ofthisThis Memo ThisInternet-Draftdocument issubmitted in full conformance withnot an Internet Standards Track specification; it is published for informational purposes. This is a contribution to theprovisionsRFC Series, independently ofBCP 78any other RFC stream. The RFC Editor has chosen to publish this document at its discretion andBCP 79. Internet-Draftsmakes no statement about its value for implementation or deployment. Documents approved for publication by the RFC Editor areworking documentsnot a candidate for any level oftheInternetEngineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The listStandard; see Section 2 of RFC 5741. Information about the currentInternet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximumstatus ofsix monthsthis document, any errata, and how to provide feedback on it may beupdated, replaced, or obsoleted by other documentsobtained atany time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on April 22, 2013.http://www.rfc-editor.org/info/rfc6812. Copyright Notice Copyright (c)20122013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document.Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.ProtocolTerminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Protocol . .3 2.1. Control Phase. . . . . . . . . . . . . . . . . . . . . .5 2.1.1.. . . 4 3.1. ControlRequestPhase . . . . . . . . . . . . . . . . . . . . . . 62.1.1.1. Command Header3.1.1. Control-Request Message . . . . . . . . . . . . . . . 6 3.1.1.1. Command-Header . . . . . . . . . . . . . . . . . . 72.1.1.2.3.1.1.2. CSLDs . . . . . . . . . . . . . . . . . . . . . . 92.1.2. Control Response3.1.2. Control-Response Message . . . . . . . . . . . . . . . 152.2.3.2. Measurement Phase . . . . . . . . . . . . . . . . . . . . 163.4. ImplementationnotesNotes . . . . . . . . . . . . . . . . . . . . . 194.5. Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . 205.6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 216.7. Security Considerations . . . . . . . . . . . . . . . . . . . 236.1.7.1. Message Authentication . . . . . . . . . . . . . . . . . . 236.2. IPSec7.2. IPsec Considerations . . . . . . . . . . . . . . . . . . . 246.2.1.7.2.1. Control Traffic . . . . . . . . . . . . . . . . . . . 246.2.2.7.2.2. Measurement Traffic . . . . . . . . . . . . . . . . . 246.3.7.3. Replay Protection . . . . . . . . . . . . . . . . . . . . 257. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 258. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 26 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26 9.1. Normative References . . . . . . . . . . . . . . . . . . . 26 9.2. Informative References . . . . . . . . . . . . . . . . . . 26Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 271. IntroductionNetworkActive network performance measurements are becoming critical data points for administrators monitoring the health of the network. AsService Providersservice providers look to differentiate their offerings, performance measurement is increasingly becoming an important tool to monitorService Levelservice-level guarantees and, in general, to monitor the health of a network. Performance metrics, both one-way and two-way, can be used for pre- deployment validation as well as for measuring in-band livenetworknetwork- performance characteristics. It can be used to measure service levels in L2 and L3 networks as well as for applications running on top of L3.PerformanceActive performance measurements are gathered by analyzingactivelysynthetically generatedsyntheticrequest and responsepackets/frames.packets or frames. This is in contrast to passive measurements that analyzeproductionlive traffic flowing through a particular network element. There is a growing body of work on Performance Measurement standards that enable interoperability between differentvendorsvendors' network elements by describing common measurement protocols as well as metrics. The IETF has actively developedstandardsStandards Track documents on thesubject and twosubject, suchstandards are One-Wayas "A One-way Active MeasurementProtocol(OWAMP)Protocol (OWAMP)" [RFC4656] andTwo-Way"Two-Way Active Measurement Protocol(TWAMP)(TWAMP)" [RFC5357]. Cisco's SLA Protocol is another example of aperformance measurementPerformance Measurement protocol that offers a rich set of measurement message types. The measurement types can be classified as those that test connectivity (ping like) by providinground trip or,round-trip or one-way latencymeasuresmeasures, and those that provide a richer set of statistics including network jitter andpacket/framepacket or frame loss. Each type of active measurementexchanges mimicexchange mimics an actual protocol exchange. Cisco's SLA ProtocolUDP measurementUDP-Measurement message exchanges, as covered in this document to enable interoperability,simulatessimulate a UDP application and can be used to simulate either Voice or Video traffic that is encoded in RTP frames within UDP envelopes. TheUDP measurement typeMeasurement-Type UDP-Measurement message exchanges carry information that provide the ability to derive a robust set of statistics. 2. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. +-------------+-----------------------------------------------------+ | Term | Description | +-------------+-----------------------------------------------------+ | Control | A phase during which a Control-Request and Control- | | Phase | Response are exchanged. | | --------- | -------------------------- | | L2 | OSI Data-Link Layer | | --------- | -------------------------- | | L3 | OSI Network Layer | | --------- | -------------------------- | | Measurement | Active Measurement Phase that is marked by a | | Phase | sequence of Measurement-Request and Measurement- | | | Response exchanges. | | --------- | -------------------------- | | Metric | A particular characteristic of the network data | | | traffic, for example, latency, jitter, packet or | | | frame loss. | | --------- | -------------------------- | | Responder | A network element that responds to a message. | | --------- | -------------------------- | | RTP | Real-time Transport Protocol | | --------- | -------------------------- | | Sender | A network element that is the initiator of a | | | message exchange. | | --------- | -------------------------- | | Service- | This is the level of service that is agreed upon | | Level | between the Provider and the Customer. | | --------- | -------------------------- | | UDP | User Datagram Protocol | +-------------+-----------------------------------------------------+ 3. Protocol The CiscoService Level AssuranceSLA Protocol consists of two distinctphases,phases: the ControlphasePhase and the Measurementphase.Phase. Each phase is comprised ofexchange ofinformation exchanged between a network element acting as the Sender andanotheran element designated as the Responder. The Control Phase is the first phase of message exchanges and forms the base protocol. This phase establishes the identity of the Sender and provides information for the Measurement Phase. A single message pair ofControl RequestControl-Request andControl ResponseControl-Response marks this phase. The Sender initiates aControl RequestControl-Request message that is acknowledged by the Responder with aControl ResponseControl-Response message. TheControl RequestControl-Request may be sent multiple times if aControl ResponseControl-Response has not been received; the number of times the message is retried is configurable on the Sender element. The Measurement Phase forms the second phase and is comprised of a sequence ofRequest/ResponseMeasurement-Request and Measurement-Response messages. These messages may be exchanged as often as required. EachMeasurement RequestMeasurement-Request message is acknowledged by the Responder with aMeasurement Response Message.Measurement-Response message. The number and frequency with which messages are sent SHOULD be controlled by configuration on the Sender element, along with the waiting time for aControl Response.Control-Response. The following sequence diagram depicts the message exchanges: +-+-+-+-+-+-+-+Control RequestControl-Request +-+-+-+-+-+-+-+ | | | | | Sender | | Responder | | | | | | | | | +-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+ | | |Control RequestControl-Request | | -------------------------------------------->| | | |Control ResponseControl-Response | |<---------------------------------------------| | | | | |Measurement Request(1)Measurement-Request(1) | | -------------------------------------------->| | | |Measurement Response(1)Measurement-Response(1) | |<---------------------------------------------| | | . . . . . . . . .Measurement Request(n)Measurement-Request(n) . | -------------------------------------------->| | | |Measurement Response(n)Measurement-Response(n) | |<---------------------------------------------| | |2.1.3.1. Control Phase The Control Phase begins with the Sender sending aControl RequestControl-Request message to the Responder. TheControl RequestControl-Request message is sent to UDP port 1167 on the Responder requesting that ameasurement phaseMeasurement Phase UDP port be opened and, in addition, indicates therequested amount of time thatduration for which the port needs tobe opened for.remain open. The Responder replies by sending aControl ResponseControl-Response with an appropriate Status indicating Success when thesenderSender identity is verified(if used)and the requested UDP port was successfully opened. In all othercasescases, a non-zero Status isreturned.returned in the Command-Header Status field. The sequence of exchanges is as indicated in thediagram.following diagram: +-+-+-+-+-+-+-+Control RequestControl-Request +-+-+-+-+-+-+-+ | |------------------------------->| | | Sender | | Responder | | |Control ResponseControl-Response | | | |<-------------------------------| | +-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+2.1.1. Control Request3.1.1. Control-Request Message TheControl RequestControl-Request message consists of aCommand HeaderCommand-Header followed by one or more Command, Status, Length and Data sections (henceforth known as CSLD). Atthea minimum, there SHOULD beat the leasttwo CSLD sections, one of which is the authentication CSLD section and the other carries information for the Measurement Phase simulation type. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + + |Command HeaderCommand-Header | + + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Command | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Command LengthCommand-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Data . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Command | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Command LengthCommand-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Data . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+2.1.1.1. Command Header3.1.1.1. Command-Header TheCommand HeaderCommand-Header is the first section of theControl RequestControl-Request message and is depicted below: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Version = 2 | Reserved | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Total Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Send Timestamp | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TheCommand HeaderCommand-Header fields hold the following meaning: +-----------+-----------+-------------------------------------------+ | Field | Size |UsageDescription | | | (bits) | | +-----------+-----------+-------------------------------------------+ | Version | 8 | Current version supported and is to be | | | | set to 2. | | --------- | --------- | -------------------------- | | Reserved | 8 | Reserved field, MUST be set to00. | | --------- | --------- | -------------------------- | | Status | 16 | Indicates success or failure for the | | | | entiremessage; not used for request andmessage. In a Control-Request, the| | | | value of the Status field is ignored by |MUST| | | the receiver and SHOULD be set to00. | | --------- | --------- | -------------------------- | | Sequence | 32 | Used to map requests to responses. This | | Number | | is a monotonically increasing number. | | | | Implementations MAY reset the sequence | | | | number to 0 after a reboot, and it SHOULD | | | | wrap around after all bits have been | | | | exceeded. | | --------- | --------- | -------------------------- | | Total | 32 | Carries the total length of thecontrolControl | | Length | | message in number ofoctetsoctets. | | --------- | --------- | -------------------------- | | --------- | --------- | -------------------------- | | Send | 64 | This field is set to the time the command | | Timestamp | | was submitted for transmission and is | | | | updated for a response. This field MAY | | | | be used when security is of concern in | | | | order to prevent replay attacks. SHOULD | | | | be updatedfor a response. When notwhen the response is sent. | | | | When not beingusedused, it MUST be set toall 0's. |all| | | | 0's. The format is as given inRFC5905RFC 5905. | +-----------+-----------+-------------------------------------------+ Thesequence numberSequence Number field MUST include a new number for each new request and is monotonically increasing. When theControl RequestControl-Request is to be retried, the sequence number MUST remain unchanged.2.1.1.2.3.1.1.2. CSLDs The ordered list of the two CSLDs to beincluded, in order,included along with theCommand HeaderCommand-Header are: o The Authentication CSLD o AMeasurement TypeMeasurement-Type CSLD In this revision of the protocol, only a singleMeasurement TypeMeasurement-Type CSLD has been defined, theUDP Measurement TypeUDP-Measurement CSLD. For futureextensionsextensions, it is possible to addadditional Measurement Typemore Measurement-Type CSLDs. For moredetails pleasedetails, seethe sectionSection 5 onExtensions. 2.1.1.2.1.extensions. 3.1.1.2.1. Authentication CSLD The Authentication CSLD providesthemessage authentication and verifies that the requester knows theshared-secret.shared secret. The following is the format for the AuthenticationCSLDCSLD: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Command = 1 | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Command LengthCommand-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Mode | Reserved | Key Id | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Random Number + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + + | | . . . . . Message Authentication Digest . . . . . | | + + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The fields for the Authentication CSLD have the followingmeaningmeaning: +----------------+-----------+--------------------------------------+ | Field | Size | Description | | | (bits) | | +----------------+-----------+--------------------------------------+ | Command | 16 | Indicates the CSLD is of type | | | |AuthenticationAuthentication. | | --------- | --------- | -------------------------- | | Status | 16 | Not used for a request and MUST be | | | | set to00. | | --------- | --------- | -------------------------- | |Command LengthCommand-Length |1632 | Indicates the length of the CSLD in | | | | octets. | | --------- | --------- | -------------------------- | | Mode | 8 | Indicates the type of authentication | | | | being used and is set as follows:0| | | | 0 - No Authentication, | | | | 1 - SHA256 Authentication, | | | |Authentication,2 - HMAC-SHA-256 | | --------- | --------- | -------------------------- | | Reserved | 8 | This field is reserved for future | | | | extensions and MUST be set to00. | | --------- | --------- | -------------------------- | | Key ID | 16 | Indicates the index number of the | | | |shared-secretshared secret to be used for | | | | authenticating theControl RequestControl-Request | | | |Messagemessage. | | --------- | --------- | -------------------------- | | Random Number | 128 | This field is to be unique over the | | | |shared secretshared-secret life and is used to | | | | make it difficult to predict the | | | | shared secret via multiple packet | | | | captures. The value is reflected in | | | | a response message. This field MAY | | | | be used when security is of concern | | | | and is useful to prevent dictionary | | | | attacks. When not beingusedused, it | | | | should be set to all 0's | | --------- | --------- | -------------------------- | | Message | 256 | Contains the message authentication | | Authentication | | digest and is computed over the | | Digest | | entire controlpacketpacket, includingthis |this| | | | field set to all0s0s. | +----------------+-----------+--------------------------------------+2.1.1.2.2. UDP Measurement3.1.1.2.2. UDP-Measurement CSLD TheUDP MeasurementUDP-Measurement CSLD indicates theMeasurement TypeMeasurement-Type to be used during the Measurement Phase and specifies the addresses and UDP port to be opened as well as the duration that the port has to be kept open for themeasurement phase.Measurement Phase. The format of the CSLD is as follows: 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Command = 2 | Status | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Command lengthCommand-Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Address Type | Role | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | Control Source Address | + + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + + | Control Destination Address | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + + | Measurement Source Address | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + + | Measurement Destination Address | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Control Source Port | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Measurement Source Port | Measurement Destination Port | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Duration | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Note: Duration is specified inseconds.milliseconds. The fields in theUDP MeasurementUDP-Measurement CSLD have the following meaning: +-------------+-----------+-----------------------------------------+ | Field | Size |DefinitionDescription | | | (bits) | | +-------------+-----------+-----------------------------------------+ | Command | 16 | Indicates that the CSLD is to simulate | | | | UDP traffic measurements. | | --------- | --------- | -------------------------- | | Status | 16 | Not used for a request and MUST be set | | | | to00. | | --------- | --------- | -------------------------- | |CommandCommand- | 32 | Indicates the length of the CSLD in | | Length | | octets. | | --------- | --------- | -------------------------- | | Address | 8 | Indicates the address type and is set|to| | Type | |toone of the values in theCisco | | | | Service Level Performance Measurement"Cisco SLA | | | | Protocol-Address FamilyRegistry. (1Registry": | | | | 2 - IPv4 addresses,23 - IPv6addresses)addresses. | | --------- | --------- | -------------------------- | | Role | 8 | Indicates the role of the endpoint | | | | receiving thecontrolControl message and is | | | | set as follows: 1 -ResponderResponder. | | --------- | --------- | -------------------------- | | Reserved | 16 | Reserved and MUST be set to00. | | --------- | --------- | -------------------------- | | --------- | --------- | -------------------------- | | Session | 32 | Carries a session identifier that is a | | Identifier | | locally significant unique value to the | | | | originator of the message. MUST be 0 | | | | when not specified. | | --------- | --------- | -------------------------- | | Control | 128 | Set to the address from which the | | Source | | Sender initiatescontrolControl messages. For | | Address | | IPv4addressesaddresses, only the first 32 bits | | | | are filled and the remaining bits MUST | | | | be set to00. | | --------- | --------- | -------------------------- | | Control | 128 | Set to the address on the Responder | | Destination | | where thecontrolControl message will be sent. | | Address | | For IPv4addressesaddresses, only the first 32 | | | | bits are filled and the remaining bits | | | | MUST be set to00. | | --------- | --------- | -------------------------- | | Measurement | 128 | Set to the address of the Sender from | | Source | | where the measurement packets will | | Address | | originate. For IPv4addressesaddresses, onlythe |the| | | | first 32 bits are filled and the | | | | remaining bits MUST be set to00. | | --------- | --------- | -------------------------- | | Measurement | 128 | Set to the address on the Responder | | Destination | | towards which the measurement packets | | Address | | will be sent and is a way to identify | | | | an ingress interface on the Responder. | | | | For IPv4addressesaddresses, only the first 32 | | | | bits are filled and the remaining bits | | | | MUST be set to00. | | --------- | --------- | -------------------------- | | Control | 16 | Indicates the port on the Sender from | | Source Port | | which the Control message is sent. If | | | |unsetnot set, the value should be derivedfrom| | | | from the incoming packet. | | --------- | --------- | -------------------------- | | Reserved | 16 | Reserved Field, MUST be set to 0. | | --------- | --------- | -------------------------- | | Measurement | 16 | Indicates the UDP Port on the Sender | | Source Port | | from which the measurement packets will | | | | besentsent. | | --------- | --------- | -------------------------- | | Measurement | 16 | Indicates the UDP Port on the Responder | | Destination | | towards which the measurement packets | | Port | | will besentsent. | | --------- | --------- | -------------------------- | | --------- | --------- | -------------------------- | | Duration | 32 | This is the duration inseconds themilliseconds | | | | that the port needs to be kept open for | | | | acceptingmeasurement phaseMeasurement Phase messages. | | | | Measurement messages received after the | | | | duration MUST beignoredignored. | +-------------+-----------+-----------------------------------------+ Note: The source addresses are only indicative of identity of the originator and cannot be used as a destination address for responses in a NAT environment.2.1.2. Control Response3.1.2. Control-Response Message In response to theControl Request MessageControl-Request message, the network element designated the Responder sends back aControl Response MessageControl-Response message that reflects theCommand HeaderCommand-Header with an updated Status field and includes the two CSLD sections that also carry updated Status fields. Hence, the format is identical to theControl RequestControl-Request message as described above.FollowingThe following table shows the supported values of the Status fields: +-----------+-------------------------------------------------------+ | Status | Description | | Value | | +-----------+-------------------------------------------------------+ | 0 | Success | | --------- | -------------------------- | | 1 | Fail - catch all | | --------- | -------------------------- | | 2 | Authentication Failure | | --------- | -------------------------- | | 3 | Format error - sent when any CSLD type is not | | | recognized or any part of a CSLD has a value that is | | | not recognized | | --------- | -------------------------- | | 4 | Port in use - the UDP/TCP port is already being used | | | by some other application and cannot be reserved | | --------- | -------------------------- | | 5+ | Future extension and experimentalvalues, pleasevalues; refer to | | |refer tothe "Cisco SLA Protocol Status TypesRegistryRegistry" in theIANA| | | Considerations section (Section 6). | +-----------+-------------------------------------------------------+ TheCommand HeaderStatus field values are applicable to both Command-Header and CSLD sections. In a Command-Header, the Status field indicates Success only if all the CSLD sections have their Statusasset to Success.ItThe Command-Header Status field is set to non-zero otherwise. The Status field in a Command-Header SHOULD only make use of status values 0 through 3, whereas CSLDs can also make use of other status values as applicable. Future extensions MAY extend these values as appropriate. TheControl ResponseControl-Response message,besides the update ofaside from updating the Status fields, SHOULD also update the Sent Timestamp (if used) in theCommand HeaderCommand-Header and the Message Authentication Digest in the Authentication CSLD. The Message Authentication Digest is computed in the same way as theControl RequestControl-Request message. The Random Number field MUST be reflected without modification. The Session Identifier MAY be updated to reflect a locally significant uniquevalue,value; it MUST be 0 if not specified.2.2.3.2. Measurement Phase Upon receiving theControl ResponseControl-Response message with the Status set to Success, the second phase of the protocol, the Measurement Phase, is initiated. In all other cases when the Status is notsuccessset to Success, no measurement traffic is initiated. In the MeasurementPhasePhase, the Sender sends a stream of measurement messages. The measurement message stream consists ofpackets/framespackets or frames that are spaced a configured number of milliseconds apart. +-+-+-+-+-+-+-+Measurement Request(n)Measurement-Request(n) +-+-+-+-+-+-+-+ | |------------------------------->| | | Sender | | Responder | | |Measurement Response(n)Measurement-Response(n) | | | |<-------------------------------| | +-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+ The format of theMeasurementmeasurement messages as defined by this document forUDP MeasurementsUDP-Measurements is as shown below and is the same for the exchange in bothdirections, that isdirections. That is, the format is the same when sent from the Sender to the Responder and when sent back from the Responder to the Sender with the only difference being the update of those fields that are designated with the Responderprefix,prefix; all other fields MUST remain unchanged. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Measurement TypeMeasurement-Type = 3 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender Send Time | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Responder Receive Time | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Responder Send Time | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender Receive Time | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender Clock Offset | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Responder Clock Offset | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sender Sequence No. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Responder Sequence No. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Data . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The fields for theUDP Measurement RequestUDP-Measurement Measurement-Request have the following meaning: +-------------+-----------+-----------------------------------------+ | Field | Size | Description | | | (bits) | | +-------------+-----------+-----------------------------------------+ |Measurement |Measurement-| 16 | Carries the type of measurement being | | Type | | performed; 1 - Reserved, 2 - Reserved, | | | | 3 -UDPUDP-Measurement | | --------- | --------- | -------------------------- | | Reserved | 16 | Reserved field and MUST be set to00. | | --------- | --------- | -------------------------- | | Sender Send | 64 | Carries the timestamp when the | | Time | | measurement message was submitted for | | | | transmission bySenderthe Sender. | | --------- | --------- | -------------------------- | | Responder | 64 | Carries the timestamp when the | | Receive | | measurement message was received by | | Time | |Responderthe Responder. | | --------- | --------- | -------------------------- | | Responder | 64 | Carries the timestamp when the | | Send Time | | measurement message was submitted for | | | | transmission by the Responder. It MUST | | | | be 0 in theSender to ResponderSender-to-Responder | | | |directiondirection. | | --------- | --------- | -------------------------- | | Sender | 64 | Carries the timestamp when the Sender | | Receive | | received the measurement message. It | | Time | | MUST be 0 in both directions on the | | | | wire and is filled on the Sender side | | | | as soon as the measurement message is | | | |receivedreceived. | | --------- | --------- | -------------------------- | | Sender | 64 | Gives an estimate of the Sender clock | | Clock | | skew measured insecondseconds and fractional | | Offset | |secondsseconds. | | --------- | --------- | -------------------------- | | Responder | 64 | Gives an estimate of the Responder | | Clock | | clock skew measured in seconds and | | Offset | | fractionalsecondsseconds. | | --------- | --------- | -------------------------- | | Sender | 32 | The sequence number of the measurement | | Sequence | | message on the Sender side. This field | | Number | | is monotonically increasing and MAY | | | |wraparoundwrap around. | | --------- | --------- | -------------------------- | | --------- | --------- | -------------------------- | | Responder | 32 | The sequence number of the measurement | | Sequence | | message on the Responder side. This | | Number | | field is monotonically increasing and | | | | MAYwraparoundwrap around. | | --------- | --------- | -------------------------- | | Data | 32 bit | This field is used to pad up to the | | | aligned | configured request data size. The | | | | minimum size for this field SHOULD be | | | | 64 octets. | +-------------+-----------+-----------------------------------------+ Note: All timestamps have the default format as described in RFC 5905 [RFC5905] and is as follows: the first 32 bits represent the unsigned integer number of seconds elapsed since0h0 h on 1 January 1900; the next 32 bits represent the fractional part of a second thereof. The timestamp definition is also similar to that described in RFC 4656[RFC4656][RFC4656]. In addition, the timestamp format used can be as described for the low-order 64 bits of the IEEE 1588-2008 (1588v2) Precision Time Protocol timestamp format [IEEE1588]. This truncated format consists of a 32-bit seconds field followed by a 32-bit nanoseconds field, and is the same as the IEEE 1588v1 timestamp format. This timestamp definition is similar to the default timestampasspecified in RFC 6374 [RFC6374] Implementations MUST use only one of the two formats. The chosen format is negotiated out-of-band between the endpoints or defaults to the format as defined in RFC 5905. [RFC5905]3.4. ImplementationnotesNotes Responder implementations SHOULD support simultaneous measurements destined to a single port either from the same or a different Sender. For different measurement instances that originate from the samesender,Sender, there MUST be a clear method for the Responder to distinguish the traffic, forexampleexample, per a unique 5-tuple of protocol, source address, source port, destinationaddressaddress, and destination port. AControl RequestControl-Request that is received for the samemeasurementMeasurement-Type request as identified by the 5-tuples, for instance, SHOULD result in the resetting of the duration timer as well as the ResponderSequence Number.sequence number. A Control Phase followed by the Measurement Phase can be repeated in order to have a continuous measurement over the entiretimelifetime of adevice is alive.device. The Authentication CSLD MUST always be included. The Random Number fieldin the Measurement packetsis used to prevent dictionary attacks and is to be set to a random value in environments where security is aconcern and is used to prevent dictionary attacks. Itconcern. An implementation MUSTalways be included,include the Random Number and Message Authentication fields whennot used it MUST be set to all 0s.the mode is non-zero. TheAuthentication CSLD MUST alwaysfields MAY beincluded. Whenincluded when the modefieldis set to0, the Random Number field and the Message Authentication Digest'No Authentication'; when present, they MUSTbothbe set toall 0s.0. For the SHA256 authenticatormodemode, the shared secret is prepended to the ControlMessagemessage and the authentication algorithm is then run over the complete data including the shared secret. The SHA256 mode is included for ease ofimplementationimplementation, andit is recommended touse of the HMAC variantto afford betteris strongly recommended for stronger security. If the UDP port indicated in theUDP MeasurementUDP-Measurement CSLD is busy, the Responder MAY suggest an alternative port, in which case the Status of theUDP MeasurementUDP-Measurement CSLD MUST be set toSuccess in that case.Success. The Sender MAY set a value of 0 in the field, in which case the Responder MAY choose to open a port and send that back along with the Statusofset to Success. It should be noted that this behavior has security ramifications and the port needs to be chosen very carefully by the Responder. The measurement stream typically consists ofpackets/framespackets or frames with a periodic inter-packet distribution. The Sender need not wait for aMeasurement ResponseMeasurement-Response packet to arrive before sending anotherMeasurement Request packet, andMeasurement-Request packet; in manycasescases, it will not be possible to wait in order to maintain the desired inter-packet distribution. The default format for all timestamps is as specified in RFC5905. [RFC5905]5905 [RFC5905]. All messages andallfields within a message are assumed to be in network order. In addition, all data fields are unsigned unless mentioned otherwise.4.5. Extensions This section describes how the protocol can be extended to allow for additional functionality, such as new types of measurements. In order to allow for new types of measurements, additionalMeasurement TypeMeasurement-Type CSLDs can be defined to be carried within theControl RequestControl-Request andControl ResponseControl-Response messages in place of theUDPUDP- Measurement CSLD defined in thisdocument .document. The meaning and precise format of such a CSLD needs to be defined in a separate specification. Such a specification will also need to describe the appropriate formats for the messages in the Measurement Phase. In addition, the protocol can be extended by adding support for new values to registries defined in this document.5.6. IANA Considerations Thefollowingregistries defined below are needed for the extensibility of theprotocol andprotocol. In the registries, the terms 'Private Use' and 'Experimental Use'found in the registries in this sectionhave the same meaning as described in RFC 5226 [RFC5226]. Furthermore, for the following registries, the ranges designated"Available for future extensions" will be"Unassigned" are governed by the policy 'RFC Required' as described in RFC 5226 [RFC5226]. CiscoService Level AssuranceSLA Protocol-Version Number Registry+-----------+---------------------------------++-----------+------------------------+ | Version | Description |+-----------+---------------------------------++-----------+------------------------+ | 0 | Reserved | | 1 | Reserved | | 2 | Version 2 | | 3 - 200 |Available for future extensionsUnassigned | | 201 - 225 | Private Use | | 226 - 255 | Experimental Use |+-----------+---------------------------------++-----------+------------------------+ The version number should be changed only when the structure of the CommandMessagesmessages is different from the basicCommand HeaderCommand-Header and CSLD structure described in this document. CiscoService Level AssuranceSLA Protocol-CSLD Command Registry+---------------+---------------------------------++---------------+--------------------------+ | CSLD Type | Description |+---------------+---------------------------------++---------------+--------------------------+ | 0 | Reserved | | 1 | Authentication CSLD | | 2 |UDP MeasurementsUDP-Measurement | | 3 - 52 | Reserved | | 53 - 10239 |Available for future extensionsUnassigned | | 10240 - 20479 | Private Use | | 20480 - 65535 | Experimental Use |+---------------+---------------------------------++---------------+--------------------------+ It is envisioned that future documents will provide their ownmeasurement typeMeasurement-Type numberalong with theand format of the Data portion. CiscoService Level AssuranceSLA Protocol-Authenticator Modes Registry+-----------+---------------------------------++-----------+--------------------------+ | Mode | Description |+-----------+---------------------------------++-----------+--------------------------+ | 0 | No Authentication | | 1 | SHA256 | | 2 | HMAC-SHA-256 | | 3 - 200 |Available for future extensionsUnassigned | | 201 - 225 | Private Use | | 226 - 255 | Experimental Use |+-----------+---------------------------------++-----------+--------------------------+ CiscoService Level AssuranceSLA Protocol-Roles Registry+-----------+---------------------------------++-----------+--------------------------+ | Role | Description |+-----------+---------------------------------++-----------+--------------------------+ | 0 | Reserved | | 1 | Sender | | 2 | Responder | | 3 - 200 |Available for future extensionsUnassigned | | 201 - 225 | Private Use | | 226 - 255 | Experimental Use |+-----------+---------------------------------++-----------+--------------------------+ CiscoService Level AssuranceSLA Protocol-Measurement Type Registry+------------------+---------------------------------++------------------+------------------------+ | Measurement Type | Description |+------------------+---------------------------------++------------------+------------------------+ | 0 | Reserved | | 1 | Reserved | | 2 | Reserved | | 3 | UDP | | 4 - 52 | Reserved | | 53-10239 |Available for future extensionsUnassigned | | 10240 - 20479 | Private Use | | 20480 - 65535 | Experimental Use |+------------------+---------------------------------++------------------+------------------------+ The following registry is also needed for the extensibility of theprotocol, however,protocol. However, the range designated"Available for future extensions" will be"Unassigned" is governed by the policy 'First Come First Served' as described in RFC 5226[RFC5226][RFC5226]. CiscoService Level AssuranceSLA Protocol-Status Types Registry +-----------+-------------------------------------------------------+ | Status | Description | +-----------+-------------------------------------------------------+ | 0 | Success | | --------- | -------------------------- | | 1 | Fail - catch all | | --------- | -------------------------- | | 2 | Authentication failure | | --------- | -------------------------- | | 3 | Format error - sent when any CSLD type is not | | | recognized or any part of a CSLD has a value that is | | | not recognized | | --------- | -------------------------- | | 4 | Port in use - the UDP/TCP port is already being used | | | by some other application and cannot be reserved | | --------- | -------------------------- | | 5 - 40959 |Available for future extensionsUnassigned | | --------- | -------------------------- | | 40960 - | Experimental Use | | 65535 | | +-----------+-------------------------------------------------------+ Finally, the following registry is also needed for the extensibility of theprotocol, however,protocol. However, the range designated"Available for future extensions" will be"Unassigned" is governed by the policy 'Specification Required' as described in RFC 5226[RFC5226][RFC5226]. CiscoService Level AssuranceSLA Protocol-Address Family Registry+--------------+---------------------------------++--------------+------------------------+ | Address Type | Description |+--------------+---------------------------------++--------------+------------------------+ | 0 | Reserved | |11 | Reserved | | 2 | IPv4 | |23 | IPv6 | |34 - 200 |Available for future extensionsUnassigned | | 201 - 225 | Private Use | | 226 - 255 | Experimental Use |+--------------+---------------------------------+ 6.+--------------+------------------------+ 7. Security Considerations6.1.7.1. Message Authentication When the mode for the Authentication CSLD is set to 1, the Message Authentication Digest is generated using theSHA 256SHA256 algorithm and is to be calculated over the entire packet including the Message Authentication Digestfieldfield, which MUST be set to all 0s. When the mode for the Authentication CSLD is set to 2, the Message Authentication Digest is generated using the HMAC-SHA-256 algorithm as described in RFC 4868[RFC4868]algorithm[RFC4868] and is to be calculated over the entire packet including the Message Authentication Digestfieldfield, which MUST be set to all0s0s. When the mode field is set to 0, the Random Numberfieldand the Message Authentication Digest fields MAY be included; when present, they MUSTbothbe set to all 0s.6.2. IPSec7.2. IPsec Considerations It is RECOMMENDED thatIPSecIPsec be employed to afford better security.IPSecIPsec provides enhanced privacy as well as an automatedkeykey- distribution mechanism. Thefollowingrecommendations below are similar toRFC3579,those in Section 2[RFC3579] 6.2.1.of RFC 3579 [RFC3579]. 7.2.1. Control Traffic For Senders implementing this specification, theIPSecIPsec policy would be "InitiateIPSec,IPsec, from me to any, destination port UDP 1167". This causes the Sender to initiateIPSecIPsec when sendingControlcontrol traffic to any Responder. If some Responders contacted by the Sender do not supportIPSec,IPsec, then a more granular policy will be required, such as "InitiateIPSec,IPsec, from me toIPSec-Capable-Responder,IPsec-Capable-Responder, destination port UDP 1167". For Responders implementing this specification, theIPSecIPsec policy would be "RequireIPSec,IPsec, from any to me, destination port UDP 1167". This causes the Responder to require use ofIPSec.IPsec. If some Sender does not supportIPSec,IPsec, then a more granular policy will be required: "RequireIPSec,IPsec, fromIPSec-Capable-SenderIPsec-Capable-Sender to me".6.2.2.7.2.2. Measurement Traffic As the Control Phase occurs before the Measurement Phase, it should be possible to build anIPSecIPsec Security Association once a successfulControl ResponseControl-Response is received. For Senders implementing this specification, theIPSecIPsec policy would be "InitiateIPSec,IPsec, from me to negotiated address, destination is negotiated port". This causes the Sender to initiateIPSecIPsec when sendingMeasurementmeasurement traffic to the Responder. If some Responders contacted by the Sender do not supportIPSec,IPsec, then a more granular policy will be required, such as "InitiateIPSec,IPsec, from me toIPSec-IPsec- Capable-Responder, destination is negotiated port". For Responders implementing this specification, theIPSecIPsec policy would be "RequireIPSec,IPsec, from negotiated address to me, destination is negotiated port". This causes the Responder to require use ofIPSec.IPsec. If some Sender does not supportIPSec,IPsec, then a more granular policy will be required: "RequireIPSec,IPsec, fromIPSec-Capable-SenderIPsec-Capable-Sender to me, destination is negotiated port".6.3.7.3. Replay Protection For the ControlMessagesmessages, the originator of the message MAY choose to include a current value in the Sent Timestamp field indicating the time the message was submitted fortransmission,transmission; otherwise, it MUST be set to0 otherwise.0. The receiver of the message MAY choose to validate it if the timestamp is within an acceptable range. TheMeasurement Trafficmeasurement traffic described in this document contains a timestamp to indicate the sent time and hence no new field is required.7. Terminology +-------------+-----------------------------------------------------+ | Term | Description | +-------------+-----------------------------------------------------+ | Control | A phase during which Control Request and Control | | Phase | Response is exchanged. | | --------- | -------------------------- | | L2 | OSI Data Link Layer | | --------- | -------------------------- | | L3 | OSI Network Layer | | --------- | -------------------------- | | Measurement | Active measurement phase that is marked by a | | Phase | sequence of Measurement Request and Measurement | | | Response exchanges. | | --------- | -------------------------- | | Metric | A particular characteristic of the network data | | | traffic, for example latency, jitter, packet/frame | | | loss | | --------- | -------------------------- | | Responder | A network element that responds to a message | | --------- | -------------------------- | | RTP | Real-time Transport Protocol | | --------- | -------------------------- | | Sender | A network element that is the initiator of a | | | message exchange | | --------- | -------------------------- | | Service | This is the level of service that is agreed upon | | Level | between the Provider and the Customer | | --------- | -------------------------- | | UDP | User Datagram Protocol | +-------------+-----------------------------------------------------+8. Acknowledgements The authors wish to acknowledge the contributions of several key people who contributed to the current form of thedocument.document: Hanlin Fang, David Wang, Anantha Ramaiah, Max Pritikin,andMaliniVijayamohan.Vijayamohan, and Susan Boyle. 9. References 9.1. Normative References [IEEE1588] IEEE, "1588-2008 Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems", March 2008. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256,HMAC-SHA- 384,HMAC- SHA-384, and HMAC-SHA-512 with IPsec", RFC 4868, May 2007. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch, "Network Time Protocol Version 4: Protocol and Algorithms Specification", RFC 5905, June 2010. 9.2. Informative References [RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial In User Service) Support For Extensible Authentication Protocol (EAP)", RFC 3579, September 2003. [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. Zekauskas, "A One-way Active Measurement Protocol (OWAMP)", RFC 4656, September 2006. [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", RFC 5357, October 2008. [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay Measurement for MPLS Networks", RFC 6374, September 2011. Authors' Addresses Murtaza S. Chiba Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: mchiba@cisco.comURI:Alexander Clemm Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: alex@cisco.comURI:Steven Medley Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: stmedley@cisco.comURI:Joseph Salowey Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: jsalowey@cisco.comURI:Sudhir Thombare Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: thombare@cisco.comURI:Eshwar Yedavalli Cisco Systems 170 West Tasman Drive San Jose, 95134 USA Phone: 1-408-526-4000Fax: Email:EMail: eshwar@cisco.comURI: