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BGP Extended Community Attribute for QoS Marking knoll-idr-qos-attribute. Thomas Martin Knoll Chemnitz University of Technology Communication Networks Phone +49 (0)371 531 33246 Email knoll@etit.tu-chemnitz.de. Motivation.
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BGP Extended Community Attribute forQoS Markingknoll-idr-qos-attribute Thomas Martin Knoll Chemnitz University of Technology Communication Networks Phone +49 (0)371 531 33246 Email knoll@etit.tu-chemnitz.de IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Motivation Current QoS support in the (global) Internet • The current “Best Effort” packet transport in IP networks is currently being augmented by locally applied traffic separation with prioritized forwarding together with costly multi-parameter ingress classification. • Such “quality islands” exist independently, peer with BE traffic, run uncoordinated QoS concepts and might not even be known globally. • Complex approaches exist, which aim for guaranteed(parameterized) QoS support for future inter-domain peerings. Proposed improvements of the new approach • Provides knowledge about the available traffic separations and encoding. Cross-layer mapping is a novel feature. • Enables route selection and marking adoption without guarantees. • Prepare for inter-domain tunnelling with QoS based traffic separation. QoS in this approach refers to primitive traffic separation into several classes, which will experience differently prioritized forwarding behaviour in relaying nodes. Enqueueing in separate queues is thereby aspired. IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Cross-Domain QoS signalling • Originating AS advertises its prefixes and the supported QoS Class Set on several layers. • Relaying ASes signal support or ignore status and their local encoding • BGP free cores either agree on L2 Class Set or signal “ignore” status. • Tunnelling of customer traffic is preferred for transparent transport. • Differentiation between internal or transit QoS Class Set IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
4 Byte TTL Label Exp. S MPLS Label Stack Format 6 6 2 2 2 46 .. 1500 4 Bytes TPI = 8100 VLAN TCI PAD DA SA T/L DATA FCS TPI Tag Protocol Identifier VLAN TCI VLAN Tag Control Information 3 Bit User Priority Cross-Layer QoS mapping • Lack of standard based cross-layer mapping (guidelines only) • Signal provider decisions • Prepare for cross-domain tunnelling of customer trafficconsistent inter-layer QoS coupling DS-Field 0 1 2 3 4 5 6 7 DSCP ECN Class Selector Codepoints ”E-LSPs” Differentiated Services Codepoint RFC 2474 IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Status & Changes Version -02 as of July 14, 2008BGP Extended Community Attribute for QoS Marking http://tools.ietf.org/html/draft-knoll-idr-qos-attribute-02 00 -> 01: IANA, much simpler technology type enumeration, problem statement, related work, reworked aggregation, tunnelled transport of transit traffic, free processing limitations 01 -> 02: RFC3140 - PHB ID Codes for inter-domain forwarding behaviour 16 bit “Marking O” IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Definition of the QoS Marking Attribute Ext. Community Attribute The new QoS Marking Attribute is encoded as a BGP Extended Community Attribute [RFC4360]. It is therefore a transitive optional BGP attribute with Type Code 16. The Type Value has been assigned to 0x00 [IANA_EC]. 0 1 2 3 4 5 6 7 +--+--+--+--+--+--+--+--+ |0 |0 |0 |R |I |A |0 |0 | +--+--+--+--+--+--+--+--+ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0 0 0 0 0 0 0 0| Flags | QoS Set Number|Technology Type| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | QoS Marking O ( h & l ) | QoS Marking A | P. Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Next Steps • Ongoing implementation into Quagga • Thanks for comments and discussions • Technology missing ? • Aggregation now acceptable ? • Employ Class Set limit ? • Pick up suggestion for section on best path selection • Guidelines for internal/external differentiation • Asking for acceptance as wg document IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Outlook Not part of today’s agenda, but complementary BGP Class of Service Interconnection http://tools.ietf.org/html/draft-knoll-idr-cos-interconnect-00 Fancy a general 3 class Internet ? IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Backup slides IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Motivation Issues Definition sel. Mechanisms Future QoS Design Summary Selected Mechanisms of the Draft Optional transitive Attribute • Smooth integration and transparent transport across ignoring ASes • Fixed fields guarantee unchanged values / other fields for local adaptation QoS Set – Concept of “linked” together attributes • Several QoS Attributes will be included, which are virtually grouped together • Grouping not fixed to technology or DSCP etc. Technology Type • Lack of common enumeration of different layer technologies L0..2 selection • Simplified approach for simplification and scalability Processing Count • Detection of non-cooperative ASes (Count vs. diff. AS numbers in AS_PATH) • Route selection based on ’I’ flag and P. Count possible IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Motivation Issues Definition sel. Mechanisms Future QoS Design Summary Technology Type Own list lack of one consistent one & simplification +-------+-----------------------------------------------------------+ | Value | Technology Type | +-------+-----------------------------------------------------------+ | 0x00 | DiffServ enabled IP (DSCP encoding) | | 0x01 | Ethernet using 802.1q priority tag | | 0x02 | MPLS using E-LSP | | 0x03 | Virtual Channel (VC) encoding using separate channels for | | | QoS forwarding / one channel per class (e.g. ATM VCs, FR | | | VCs, MPLS L-LSPs) | | 0x04 | GMPLS - time slot encoding | | 0x05 | GMPLS - lambda encoding | | 0x06 | GMPLS - fibre encoding | +-------+-----------------------------------------------------------+ IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Motivation Issues Definition sel. Mechanisms Future QoS Design Summary BGP update message IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Related Work [I-D.jacquenet-bgp-qos] -> QOS_NLRI attribute [I-D.boucadair-qos-bgp-spec] -> based on QOS_NLRI + combined QoS parameter sets [I-D.liang-bgp-qos] -> extending AS_PATH [I-D.zhang-idr-bgp-extcommunity-qos] -> TOS value signalling [MIT_CFP] "Inter-provider Quality of Service - White paper draft 1.1“ -> 2 class strict QoS <http://cfp.mit.edu/docs/interprovider-qos-nov2006.pdf> IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll
Sources [IANA_EC] IANA, „Border Gateway Protocol (BGP) Data Collection Standard Communities“, online available http://www.iana.org/assignments/bgp-extended-communities [I-D.knoll-idr-qos-attribute] Knoll, T., "BGP Extended Community Attribute for QoS Marking", draft-knoll- idr-qos-attribute-00 (work in progress), June 2008. [MIT_CFP] Amante, S., Bitar, N., Bjorkman, N., and others, "Inter-provider Quality of Service - White paper draft 1.1",November 2006, http://cfp.mit.edu/docs/interprovider-qos-nov2006.pdf [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway Protocol 4 (BGP-4)", RFC 4271, January 2006. [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended Communities Attribute", RFC 4360, February 2006. [RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration Guidelines for DiffServ Service Classes", RFC 4594, August 2006. [Y.1541] ITU-T, “Network performance objectives for IP-based services”, Y.1541, February 2006 IETF 72 in Dublin - Inter-Domain Routing WG (IDR) - Thomas M. Knoll