Hi
Looking for some design ideas. I have 2 ISP but want symmetrical routing via primary ISP to take advantage of 100mbps WAN. I have a /29 from both ISP so R1 will EBGP with Primary and Backup. R2 will do the same - EBGP with Primary and Backup. R1 and R2 is IBGP. I will setup Local Preference at 450, 400, 350, and 300 for outbound. For inbound, I will use AS-Prepend. Below is a image and sample configs I am building.
R1
router bgp 10
no synchronization
bgp log-neighbor-changes
network 1.1.1.0 mask 255.255.255.0
neighbor PRIMARY peer-group
neighbor PRIMARY remote-as 20
neighbor PRIMARY version 4
neighbor PRIMARY soft-reconfiguration inbound
neighbor PRIMARY prefix-list DEFAULT-ONLY in
neighbor PRIMARY route-map SETLOCAL-1 in
neighbor 2.2.2.1 peer-group PRIMARY
neighbor SECONDARY peer-group
neighbor SECONDARY remote-as 30
neighbor SECONDARY version 4
neighbor SECONDARY soft-reconfiguration inbound
neighbor SECONDARY prefix-list DEFAULT-ONLY in
neighbor SECONDARY route-map SETLOCAL-2 in
neighbor SECONDARY route-map PREPEND-AS out
neighbor 3.3.3.1 peer-group SECONDARY
neighbor IBGP peer-group
neighbor IBGP remote-as 10
neighbor IBGP version 4
neighbor IBGP NEXT-HOP-SELF
neighbor IBGP soft-reconfiguration inbound
neighbor IBGP route-map IBGP-OUT out
neighbor 1.1.1.3 peer-group IBGP
no auto-summary
ip prefix-list DEFAULT-ONLY description ONLY-ALLOWED-DEFAULT-ROUTE-IN
ip prefix-list DEFAULT-ONLY seq 5 permit 0.0.0.0/0
route-map SETLOCAL-1 permit 10
set local-preference 450
route-map SETLOCAL-2 permit 10
set local-preference 350
route-map PREPEND-AS permit 10
set as-path prepend 10 10
ip prefix-list IBGP-OUT description ALLOWED-IBGP-PEER-ANNOUNCEMENTS
ip prefix-list IBGP-OUT seq 5 permit 1.1.1.0/24
---------------------------------------------
R2
router bgp 10
no synchronization
bgp log-neighbor-changes
network 1.1.1.0 mask 255.255.255.0
neighbor PRIMARY peer-group
neighbor PRIMARY remote-as 20
neighbor PRIMARY version 4
neighbor PRIMARY soft-reconfiguration inbound
neighbor PRIMARY prefix-list DEFAULT-ONLY in
neighbor PRIMARY route-map SETLOCAL-1 in
neighbor 2.2.2.1 peer-group PRIMARY
neighbor SECONDARY peer-group
neighbor SECONDARY remote-as 30
neighbor SECONDARY version 4
neighbor SECONDARY soft-reconfiguration inbound
neighbor SECONDARY prefix-list DEFAULT-ONLY in
neighbor SECONDARY route-map SETLOCAL-2 in
neighbor SECONDARY route-map PREPEND-AS out
neighbor 3.3.3.1 peer-group SECONDARY
neighbor IBGP peer-group
neighbor IBGP remote-as 10
neighbor IBGP version 4
neighbor IBGP NEXT-HOP-SELF
neighbor IBGP soft-reconfiguration inbound
neighbor IBGP route-map IBGP-OUT out
neighbor 1.1.1.2 peer-group IBGP
no auto-summary
ip prefix-list DEFAULT-ONLY description ONLY-ALLOWED-DEFAULT-ROUTE-IN
ip prefix-list DEFAULT-ONLY seq 5 permit 0.0.0.0/0
route-map SETLOCAL-1 permit 10
set local-preference 400
route-map SETLOCAL-2 permit 10
set local-preference 300
route-map PREPEND-AS permit 10
set as-path prepend 10 10
ip prefix-list IBGP-OUT description ALLOWED-IBGP-PEER-ANNOUNCEMENTS
ip prefix-list IBGP-OUT seq 5 permit 1.1.1.0/24
