Internet-Draft B. Berry, Editor Intended status: Informational S. Ratliff Expires: February 28, 2008 E. Paradise Cisco T.Kaiser Harris Corporation M. Adams L3 Communications September 10, 2007 PPP Over Ethernet (PPPoE) Extensions for Scaled Credits and Link Metrics draft-bberry-pppoe-scaled-credits-metrics-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 28, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document specifies a method for optional flow control credit scaling and link quality metric scaling for Point-to-Point over Ethernet (PPPoE). Scaling is required when connecting to high performance devices that employ the PPPoE credit flow control and link metric reports as defined in RFC 4938. Berry, et. al. Expires February 28, 2008 [Page 1] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 1. Introduction PPP over Ethernet (PPPoE) [2] is a protocol for establishing and encapsulating sessions between hosts and traffic aggregators for PPP [1] transport over Ethernet. PPPoE [2] was extended by RFC 4938 [3], which provides Credit Flow and Link Metrics. This document specifies an enhancement to RFC 4938 [3] credit flow and metric reports to support high performance (radio) traffic aggregators. The enhancements are backward compatible to maintain the functionality of RFC4938. 2 Terminology BCN Backward Credit Notification CDR Current Data rate FCN Forward Credit Notification gbps gigabits (1,000,000,000) per second kbps kilobit (1,000) bits per second mbps megabits (1,000,000) per second MDR Maximum Data rate tbps terabits (1,000,000,000,000) per second Berry, et. al. Expires February 28, 2008 [Page 2] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 3. Overview of Credit and Metric Enhancements RFC 4938 defined credits in 64-byte units of PPP payload. This document specifies a new optional Credit Scalar Tag that can be used in the PADR-PADS exchange to modify the credit unit value. RFC 4938 defined the metrics maximum data rate and the current data rate in units of kilobits per second. With high performance devices, the need to express data rates greater than kilobits per second is needed. To support the dynamic nature of high performance radio devices, two bits for each data rate, the maximum data rate and the current data rate, are allocated from the Reserved field to specify the data rate units. The tables below show the impact of the new Credit Scalar Tag and the enhanced Metric Tag. Packet Types Packet Status ======================================================= PADR Enhanced, optionally includes the Credit Scalar Tag PADS Enhanced, optionally includes the Credit Scalar Tag PADG Unchanged PADC Unchanged PADQ Enhanced, metrics are expressed in the default units or scalar the units. Tag_Types and Tag_Values Tag Tag Value Description Status ======================================================= 0x0106 Credits Unchanged 0x0107 Metrics Modified, MD and CD bits defined 0x0108 Sequence Number Unchanged 0x0109 Credit Scalar New Berry, et. al. Expires February 28, 2008 [Page 3] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 4. Packet Enhancements 4.1. PPPoE Active Discovery Request (PADR) The PADR packet is enhanced to optionally contain a single Credit Scalar Tag TLV. The Credit Scalar Tag defines the credit unit value. If the Credit Scalar tag is omitted, the default value of 64-bytes is used for the session. This credit scalar value is applied to all credit values associated with the client. The Credit Scalar Tag is optionally permitted when the Credit Tag is included. An example packet is shown in Appendix B. 4.2. PPPoE Active Discovery Session-confirmation (PADS) The PADS packet is enhanced to optionally contain a single Credit Tag Scalar Tag TLV. The Credit Scalar Tag defines the credit unit value. If the Credit Scalar Tag is omitted, the default value of 64-bytes is used for the session. This credit scalar value is applied to all credit values associated with the server. The Credit Scalar Tag is optionally permitted when the Credit Tag is included. An example packet is shown in Appendix B. 4.3. PPPoE Active Discovery Session-Grant (PADG) The PADG packet must contain a single Credit Tag TLV, indicating the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) of the PPPoE Session. The FCN and BCN values must be scaled by the "values" established during session establishment in the Credit Scalar Tags or by the default 64-byte value prior to processing. An example packet is shown in Appendix B. Berry, et. al. Expires February 28, 2008 [Page 4] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 4.4. PPPoE Active Discovery Session-Credit Response (PADC) The PADC packet must contain a single Credit Tag TLV, indicating the Forward Credit Notification (FCN) and the Backward Credit Notification (BCN) of the PPPoE session, and any number of other Tag types. The FCN and BCN values must be scaled by the "values" established during session establishment in the Credit Scalar Tags or by the default 64-byte value prior to processing. An example packet is shown in Appendix B. 4.5. PPPoE Active Discovery Quality (PADQ) The PADQ must carry a single Metric Tag TLV. When processing the data rates, the values must be converted using the indicated data rate units. An example packet is shown in Appendix B. Berry, et. al. Expires February 28, 2008 [Page 5] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 5 TAG Enhancements 5.1 Metric Tag TLV The Metric Tag TYPE, contains the following fields: Receive only - a bit that indicates whether the link is bi- directional or receive only. A value of -1- indicates that the link is receive-only. MD - Two bits that designate the units of the maximum data rate. CD Scale: 00 == kbps 01 == mbps 10 == gbps 11 == tbps CD - Two bits that designate the units of the current data rate. CD Scale: 00 == kbps 01 == mbps 10 == gbps 11 == tbps Reserved - Reserved fields are zeroed unless otherwise specified. Maximum data rate - the maximum theoretical data rate, in scalar units per second, that the link is capable of providing. When metrics are reported, the maximum data rate must be reported. Current data rate - the current data rate, in scalar units per second, achieved on the link. If there is no distinction between maximum data rate and current data rate, current data rate should equal the maximum data rate. Berry, et. al. Expires February 28, 2008 [Page 6] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 Latency - the transmission delay that a packet encounters as it is transmitted over the Host link. This is reported in absolute delay, milliseconds. If latency cannot be calculated, a value of 0 should be reported. The calculation of latency is device dependent. For example, the latency may be a running average calculated from the internal queuing. Resources - a percentage, 0-100, representing the amount of remaining or available resources, such as battery power. If resources cannot be calculated, a value of 100 should be reported. Relative Link Quality (RLQ) - a non-dimensional number, 0-100, representing the relative link quality. A value of 100 represents a link of the highest quality. If the RLQ cannot be calculated, a value of 100 should be reported. The PPPoE Active Discovery Quality (PADQ) packet can be used to query link metrics by setting the PADQ Metric Tag Length to zero. An example tag is shown in Appendix A. 5.2 Credit Scalar Tag TLV The Credit Scalar Tag can be used to change from the default 64-byte credit unit. The new credit scalar can range from 1-byte to 65535-bytes. A zero value is ignored and the default 64-byte unit remains set. For example, if a high performance device requires credit grants in 512-bytes units, the new Credit Scalar TLV is included in the PADR-PADS exchange to set its credit flow to 512-byte units. In another example, a high performance device requires credit grants in 2048-bytes units. To set the new scalar value, the high performance device must use the Credit Scalar in the PADR-PADS exchange to set its credit flow to 2048-byte units. Berry, et. al. Expires February 28, 2008 [Page 7] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 6. IANA Considerations IANA has assigned the following PPPoE TAG Values as noted in [4]: TAG Value TAG Name Tag Description Reference ----------- ------------------- --------------------- --------- 262 0x0106 Credits See the reference [RFC4938] 263 0x0107 Metrics See the reference [RFC4938] 264 0x0108 Sequence Number See the reference [RFC4938] 265 0x0109 Credit Scalar See the reference [RFCnnnn] IANA has assigned the following PPPoE Code fields as noted in [4]: Code PPPoE Packet Name Description Reference -------- ----------------------------- ----------------- --------- 10 0x0a PADG, Session-Grant See the reference [RFC4938] 11 0x0b PADC, Session-Credit Response See the reference [RFC4938] 12 0x0c PADQ, Quality See the reference [RFC4938] 7. Security Considerations This memo defines a mechanism to scale the credit grant units and the link metrics to the existing credit-based flow control mechanism and link quality metrics of Point-to-Point over Ethernet (PPPoE). These extensions are subsequent to the existing PPPoE security mechanisms as described in RFC 2516 [2]. Berry, et. al. Expires February 28, 2008 [Page 8] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 Appendix A: Tag Values Feature Tag_Types and Tag_Values Tag Tag Value Description Status =================================== 0x0106 Credits Unchanged 0x0107 Metrics Modified 0x0108 Sequence Number Unchanged 0x0109 Credit Scalar New 0x0107 Metrics This tag is used to report the link quality and performance. The Metrics Tag contains the Receive Only indicator, Resource status, Latency, Relative Link Quality (RLQ), Current data rate, and Maximum data rate. The Metrics Tag is required by the PADQ packet. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0107 | Tag Length=0x0A | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | MD| CD|R| RLQ | Resource | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Latency (MS) | Current Datarate | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Datarate | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Berry, et. al. Expires February 28, 2008 [Page 9] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 0x0109 Credit Scalar This tag contains the scalar value that is to be applied to the session credit manipulation. The Credit Scalar Tag is OPTIONAL with the PADR, PADS packets. A value of zero is ignored and the default scalar of 64 bytes is applied. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0109 | Tag Length=0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scalar | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Berry, et. al. Expires February 28, 2008 [Page 10] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 Appendix B: Example Packet Formats A PADR packet with the Credit Tag Type 0x0106 and the OPTIONAL Credit Tag Type 0x0106: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access_Concentrator_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Access_Concentrator_mac_addr(c)| Host_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Host_mac_addr (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x19 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SESSION_ID = 0x1234 | LENGTH = 0x0C | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0101 | Tag Length=0x00 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0106 | Tag Length=0x04 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FCN | BCN=0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0109 | Tag Length=0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | scalar | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Credit Tag (0x106) FCN value is expressed in units of the session credit scalar. If the Credit Scalar Tag is omitted, the FCN is expressed in 64-byte units. Berry, et. al. Expires February 28, 2008 [Page 11] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 A PADS packet with the Credit Tag Type 0x0106 and the OPTIONAL Credit Tag Type 0x0106: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access_Concentrator_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Access_Concentrator_mac_addr(c)| Host_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Host_mac_addr (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x65 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SESSION_ID = 0x1234 | LENGTH = 0x0C | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0101 | Tag Length=0x00 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0106 | Tag Length=0x04 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FCN | BCN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0109 | Tag Length=0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | scalar | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The Credit Tag (0x106) FCN value is expressed in units of the session metric scalar received in the PADR. If the PADR did not contain the Credit Scalar Tag, the FCN is expressed in the default 64-byte units. The Credit Tag (0x106) BCN value is expressed in units of the session credit scalar contained in this PADS. If the Credit Scalar Tag is omitted, the BCN is expressed in 64-byte units. Berry, et. al. Expires February 28, 2008 [Page 12] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 A PADG packet with the Credit Tag Type 0x0106: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination_mac_addr(c) | Source_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source mac_addr (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0A | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SESSION_ID = 0x1234 | LENGTH = 0x0E | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0108 | Tag Length=0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | Tag Type = 0x0106 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Length=0x04 | FCN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BCN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The FCN and BCN values are expressed in the respective units of the session credit scalar. Berry, et. al. Expires February 28, 2008 [Page 13] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 A PADC packet with the Credit Tag Type 0x0106: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Destination_mac_addr(c) | Source_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Source mac_addr (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0B | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SESSION_ID = 0x1234 | LENGTH = 0x0E | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0108 | Tag Length=0x02 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | Tag Type = 0x0106 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Length=0x04 | FCN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BCN | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The FCN and BCN values are expressed in the respective units of the session credit scalar. Berry, et. al. Expires February 28, 2008 [Page 14] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 A PADQ packet with Metric Tag Type 0x0107 showing the scalar bits: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Access_Concentrator_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Access_Concentrator_mac_addr(c)| Host_mac_addr | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Host_mac_addr (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ETHER_TYPE = 0x8863 | v = 1 | t = 1 | CODE = 0x0C | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SESSION_ID = 0x1234 | LENGTH = 0x12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0101 | Tag Length=0x00 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Tag Type = 0x0107 | Tag Length=0x0A | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | MD| CD|R| RLQ | Resource | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Latency (MS) | Current Datarate | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Datarate | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The maximum datarate and the current datarate are expressed in units determined by the MD and CD bits, respectively. Berry, et. al. Expires February 28, 2008 [Page 15] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 Normative References [1] Simpson, W., Ed., "The Point-to-Point Protocol (PPP)", STD 51, RFC 1661, July 1994. [2] Mamakos, L., Lidl, K., Evarts, J., Carrel, D., Simone, D., and R. Wheeler, "A Method for Transmitting PPP Over Ethernet (PPPoE)", RFC 2516, February 1999. [3] Berry, B., Holgate, H., "PPP Over Ethernet (PPPoE) Extensions for Credit Flow and Link Metrics", RFC 4938, June 2007. [4] Arberg, P. and V. Mammoliti, "IANA Considerations for PPP over Ethernet (PPPoE)", RFC 4937, June 2007. Authors' Addresses Bo Berry, Editor Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: bberry@cisco.com Stan Ratliff Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: sratliff@cisco.com Ed Paradise Cisco 170 West Tasman Drive San Jose, CA 95134 EMail: pdice@cisco.com Tim Kaiser Harris Corporation Government Communications System Division Mail Stop 25-11F P.O. Box 37 Melbourne, FL 32902-0037 EMail: timothy.kaiser@harris.com Mike D Adams 640 N 2200 W MS F1J12 Salt Lake City, Utah 84116 801 594-2367 EMail: Michael.D.Adams@L-3com.com Berry, et. al. Expires February 28, 2008 [Page 16] Internet-Draft PPPoE Scaled Credits and Metrics September 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgements Funding for the RFC Editor function is currently provided by the Internet Society. Berry, et. al. Expires February 28, 2008 [Page 17]