Objectives
The simulator ticks each one as soon as the network meets it.
leaf1 (SR Linux): AS 65101, router ID 10.0.1.1, ipv4-unicast enabled, neighbor 10.1.1.1 in group "peer" with peer-as 65102.
leaf1: export its host subnet with a prefix-set policy and import everything.
leaf2 (Arista): router bgp 65102 with router-id, neighbor 10.1.1.0 remote-as 65101, and network 192.168.2.0/24.
Both leaves show the session established with one route received.
Ping PC2 from PC1.
Before you start
The same protocol, two philosophies: EOS advertises what its network statements name and accepts everything, while SR Linux exchanges nothing over eBGP until import and export policies allow it.
Concept
SR Linux eBGP: rejected in both directions until a policy allows it
SR Linux protects eBGP sessions by default: with no import policy every received route is rejected, and with no export policy nothing is advertised. The session is Established, yet no route moves until routing policies say what is allowed.
Concept
eBGP: exchanging routes between autonomous systems
BGP connects networks run by different organisations (autonomous systems). Two routers in different ASes form an eBGP session over TCP port 179 and advertise only the prefixes they choose, each tagged with the AS path it has crossed.
