57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt 57 th IETF meeting IS-IS as the PE/CE Protocol in BGP/MPLS VPN draft-sheng-ppvpn-isis-bgp-mpls-00.txt Slide 1

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt Motivation  In 2547 VPN, PE-CE routing protocol can be EBGP,OSPF,RIP,Static routing etc,IS-IS can also assume this function.  In OSPF case,there are draft-rosen and draft-ishiguro addressing the problem.  In IS-IS case,no such draft,this draft will fill the vacancy. Slide 2

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt  When IS-IS is already used in customer network. CEs need only run one routing protocol. Little impact on transition from legacy customer network.  A new choice for CE-PE routing protocol. Benefits Slide 3

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt  Fundamental Model  Assumptions No back door IS-IS link between CEs in the same VPN.  Multiple IS-IS instances (Applicable to Extended Model)  Support Multiple IS-IS instances in one PE  Each instance bound to one specific VRF.  IS-IS interaction with BGP on PE PEs have the capability to import IS-IS and BGP routes to/from each other in particular VRFs.  Import BGP routes to IS-IS as external routes,TLV 130.  Narrow IS-IS metric style:0-1023,  Wide IS-IS metric style: (2^32-2^25),TLV 135 Contents(1/5) Slide 4

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt  Extended Model  Support back door IS-IS link between CEs of the same VPN. Contents(2/5) Slide 5

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt Contents(3/5)  Extended Model  Carry IS-IS information with BGP Extended communities (first two bytes)  IS-IS Route Type Extended Communites Attribute. Level type (bit 1/byte 3rd,0/1:level 1/2) Metric style type (bit 2/byte 3rd,0/1:narrow/wide) TLV Reachability type (0/1:internal/external) Metric type (0/1: internal metric/external metric) Sham-link endpoint address (1:sham link end)  IS-IS System ID Extended Communites Attribute  MED. The value of the IS-IS distance associated with the route, plus 1. Slide 6

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt Contents(4/5)  Extended Model  Route loop prevention on PEs  PE1 and PE2 both import BGP routes into their attached CE sites, the route loop maybe happen.  To avoid the route loop, it is assumed here that both PE1 and PE2 act as L1/2 router and there exists level-1 adjacency between each PE- CE link.  Refer to RFC 2966 to avoid route loop (use up/down bit).  IS-IS interaction with BGP on PE  When Egress PE receives a VPN-IP routes, converts them back to IS-IS.  The creation of IS-IS LSP bases on IS-IS route original information carried by BGP extended communities Slide 7

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt Contents(5/5)  Extended Model  Sham-link Creation Each end PE assigns an shamlink endpoint address. BGP imports direct route designated as source shamlink endpoint address on PE2. Converted BGP route carries BGP extended communities (sham- link endpoint address bit set,IS-IS System ID Extended Communites Attribute equal to the System ID of the IS-IS instance on the PE2. PE1 receives the route, gets the IS-IS System ID in BGP route, checks the sham-link endpoint address bit, create shamlink or not. PE1 adds Neighbor reachability TLV in its self-originated LSP and floods it to CE1. Similar process will happen on PE2. When PE finds that the system ID of the other end of the sham-link is changed, flushes the old LSP and generates new LSP according to the new system ID got from BGP route. Slide 8

57 th IETF VIENNA draft-sheng-ppvpn-isis-bgp-mpls vpn-01.txt Next Step  Please review the draft  Comments are welcome  Discussion and revision  Can it progress to WG draft? Slide 9