Arista BGP-LU/SR

In this blog, talking a bit about BGP-LU/SR and its use cases.  Here are some References:

Arista BGP-LU

• By the RFC 3107, the equivalent Cisco feature is called labeled BGP. The concept is quite simple to advertise an IPv4 prefix with a label. 
• Use case 1) - replace RSVP-TE, cloud provider
• Central controllers push routes with multiple label via BGP-LU
• Replace RSVP-TE
• Use case 2) - CSC
• ce1--pe1---asbr1--[--cPE1-----cPE2--]--asbr2---pe2--ce2
• between asbr and cPE, eBGP-LU, so cPEs know the label to reach PEs
• cPEs switch packets based on labels of PEs' loopback
• Configuration:
• router bgp 100
•   bgp labeled-unitcast rib tunnel|ip
•   neighbor 77.255.11.11 remote-as 100
•   neighbor 77.255.11.11 update-source lo77
•   address-family ipv4 labeled-unicast
•     neighbor 77.255.11.11 act
• show platform jericho mpls route
• Tunnel RIB vs IP RIB
• Mutli-agent vs GateD

Arista MPLS Segment Routing WP

• 3 segment routing approaches
• 1) Static mpls push + NHG
• prefix based - 100.1.1.0/24 -> NHG1 3.3.3.3 {2, 3, 5, 8}
• class based - 100.1.1.0/24 EF -> NHG1 3.3.3.3 {1,2,3}
• 2) EOS SDK by controller
• Listen: controller leans ISIS topology SIDs (node, adj, prefix) via ISISoGRE or BGP-LS (not supported by Arista EOS yet as of Feb 2019)
• Write: program SR multi-label stack tunnel using NHG
• 3) BGP-LU
• Listen: same as 2)
• Write: use BGP-LU