[c-nsp] BGP multihoming with redundancy config problem
Ganbold
ganbold at micom.mng.net
Mon Oct 24 05:59:32 EDT 2005
Hi all,
Basically I'm trying to make BGP multihoming work with 2 different
ISPs and plus redundancy.
Followiing is the scheme:
upstream1 upstream2
\ /
\ /
upstream1 border router upstream2 border router
\ /
\ /
CORE ROUTER1 <-----------> CORE ROUTER2
/ \
/ \
Part of OUR network Part of OUR network
Following are the bgp config parts:
UPSTREAM1 border router config:
###################################
router ospf 117
log-adjacency-changes
passive-interface Hssi3/0
passive-interface Loopback0
network x.x.15.0 0.0.0.3 area 0
network x.x.0.0 0.0.0.255 area 0
network x.x.3.0 0.0.0.255 area 0
network x.x.5.0 0.0.0.255 area 0
network x.x.9.0 0.0.0.255 area 0
network x.x.10.0 0.0.0.255 area 0
!
router bgp xxxx
no synchronization
bgp log-neighbor-changes
network x.x.0.0 mask 255.255.224.0
neighbor ibgp-peers peer-group
neighbor ibgp-peers remote-as xxxx
neighbor ibgp-peers description iBGP peering for internall
neighbor ibgp-peers update-source Loopback0
neighbor ibgp-peers send-community
neighbor x.x.5.1 peer-group ibgp-peers
neighbor x.x.5.2 peer-group ibgp-peers
neighbor x.x.5.3 peer-group ibgp-peers
neighbor x.x.5.25 peer-group ibgp-peers
neighbor x.x.15.1 remote-as zzzzz
neighbor x.x.15.1 description UPSTREAM1 INTERNET GW
neighbor x.x.15.1 password 7 xxxxxxxxxxxxxxx
neighbor x.x.15.1 version 4
neighbor x.x.15.1 timers 120 360
neighbor x.x.15.1 soft-reconfiguration inbound
distance bgp 200 200 200
no auto-summary
!
ip classless
ip route x.x.0.0 255.255.224.0 Null0
ip as-path access-list 100 permit ^$
ip as-path access-list 100 deny .*
!
!
ip prefix-list default seq 5 permit 0.0.0.0/0
!
ip prefix-list myblock seq 5 permit x.x.0.0/19
!
ip prefix-list subblocks seq 10 permit x.x.1.0/24
ip prefix-list subblocks seq 15 permit x.x.2.0/24
ip prefix-list subblocks seq 20 permit x.x.5.0/24
ip prefix-list subblocks seq 30 permit x.x.8.0/24
ip prefix-list subblocks seq 35 permit x.x.10.0/24
ip prefix-list subblocks seq 40 permit x.x.16.0/24
ip prefix-list subblocks seq 45 permit x.x.17.0/24
ip prefix-list subblocks seq 50 permit x.x.18.0/24
ip prefix-list subblocks seq 55 permit x.x.19.0/24
ip prefix-list subblocks seq 60 permit x.x.21.0/24
ip prefix-list subblocks seq 65 permit x.x.24.0/24
ip prefix-list subblocks seq 70 permit x.x.25.0/24
ip prefix-list subblocks seq 75 permit x.x.28.0/24
ip prefix-list subblocks seq 80 permit x.x.30.0/24
route-map infilter permit 10
set local-preference 80
!
route-map outfilter permit 10
match ip address prefix-list subblocks
set as-path prepend xxxx xxxx xxxx
#########################################
UPSTREAM2 border router config:
###################################
router ospf 117
log-adjacency-changes
passive-interface Multilink1
passive-interface Loopback0
network x.x.0.0 0.0.0.255 area 0
network x.x.3.0 0.0.0.255 area 0
network x.x.5.0 0.0.0.255 area 0
network x.x.9.0 0.0.0.255 area 0
network x.x.10.0 0.0.0.255 area 0
network x.y.39.132 0.0.0.3 area 0
!
router bgp xxxx
no synchronization
bgp log-neighbor-changes
network x.x.1.0
network x.x.2.0
network x.x.5.0
network x.x.8.0
network x.x.10.0
network x.x.16.0
network x.x.17.0
network x.x.18.0
network x.x.19.0
network x.x.21.0
network x.x.24.0
network x.x.25.0
network x.x.28.0
network x.x.30.0
network x.x.0.0 mask 255.255.224.0
neighbor ibgp-peers peer-group
neighbor ibgp-peers remote-as xxxx
neighbor ibgp-peers description iBGP peering for internall
neighbor ibgp-peers update-source Loopback0
neighbor ibgp-peers send-community
neighbor x.x.5.1 peer-group ibgp-peers
neighbor x.x.5.2 peer-group ibgp-peers
neighbor x.x.5.3 peer-group ibgp-peers
neighbor x.x.5.4 peer-group ibgp-peers
neighbor x.y.39.133 remote-as 9800
neighbor x.y.39.133 description UPSTREAM2 BGP Peering
neighbor x.y.39.133 version 4
neighbor x.y.39.133 soft-reconfiguration inbound
neighbor x.y.39.133 prefix-list default in
neighbor x.y.39.133 prefix-list subblocks out
neighbor x.y.39.133 route-map outfilter out
distance bgp 200 200 200
no auto-summary
!
ip classless
ip route x.x.0.0 255.255.224.0 Null0
ip route x.x.1.0 255.255.255.0 Null0
ip route x.x.2.0 255.255.255.0 Null0
ip route x.x.5.0 255.255.255.0 Null0
ip route x.x.8.0 255.255.255.0 Null0
ip route x.x.10.0 255.255.255.0 Null0
ip route x.x.16.0 255.255.255.0 Null0
ip route x.x.17.0 255.255.255.0 Null0
ip route x.x.18.0 255.255.255.0 Null0
ip route x.x.19.0 255.255.255.0 Null0
ip route x.x.21.0 255.255.255.0 Null0
ip route x.x.24.0 255.255.255.0 Null0
ip route x.x.25.0 255.255.255.0 Null0
ip route x.x.28.0 255.255.255.0 Null0
ip route x.x.30.0 255.255.255.0 Null0
no ip http server
ip as-path access-list 100 permit ^$
ip as-path access-list 100 deny .*
!
!
ip prefix-list aggregate seq 5 permit x.x.0.0/19
!
ip prefix-list default seq 5 permit 0.0.0.0/0
!
ip prefix-list subblocks seq 1 permit x.x.0.0/19 le 24
route-map infilter permit 10
match ip address prefix-list default
set local-preference 80
!
route-map infilter permit 20
!
route-map outfilter permit 10
match ip address prefix-list aggregate
set as-path prepend xxxx xxxx xxxx
!
route-map outfilter permit 20
#########################################
CORE ROUTER1 which connects to UPSTREAM1 border router:
#########################################
router ospf 117
log-adjacency-changes
passive-interface Loopback0
network x.x.0.64 0.0.0.31 area 0
network x.x.0.96 0.0.0.31 area 0
network x.x.0.128 0.0.0.31 area 0
network x.x.0.160 0.0.0.31 area 0
network x.x.0.192 0.0.0.31 area 0
network x.x.3.0 0.0.0.255 area 0
network x.x.5.0 0.0.0.255 area 0
network x.x.9.0 0.0.0.255 area 0
network x.x.10.0 0.0.0.255 area 0
!
router bgp xxxx
no synchronization
bgp log-neighbor-changes
network x.x.0.0 mask 255.255.224.0
neighbor ibgp-peers peer-group
neighbor ibgp-peers remote-as xxxx
neighbor ibgp-peers description iBGP peering for internal
neighbor ibgp-peers update-source Loopback0
neighbor ibgp-peers send-community
neighbor x.x.5.2 peer-group ibgp-peers
neighbor x.x.5.3 peer-group ibgp-peers
neighbor x.x.5.4 peer-group ibgp-peers
neighbor x.x.5.25 peer-group ibgp-peers
distance bgp 200 200 200
no auto-summary
!
ip classless
ip route x.x.0.0 255.255.224.0 Null0
!
!
#########################################
CORE ROUTER2 which connects to UPSTREAM2 border router:
#########################################
router ospf 117
log-adjacency-changes
passive-interface Loopback0
network x.x.0.0 0.0.0.255 area 0
network x.x.3.0 0.0.0.255 area 0
network x.x.5.0 0.0.0.255 area 0
network x.x.9.0 0.0.0.255 area 0
network x.x.10.0 0.0.0.255 area 0
!
router bgp xxxx
no synchronization
bgp log-neighbor-changes
network x.x.0.0 mask 255.255.224.0
neighbor ibgp-peers peer-group
neighbor ibgp-peers remote-as xxxx
neighbor ibgp-peers description iBGP peering for internal
neighbor ibgp-peers update-source Loopback0
neighbor ibgp-peers send-community
neighbor x.x.5.1 peer-group ibgp-peers
neighbor x.x.5.2 peer-group ibgp-peers
neighbor x.x.5.4 peer-group ibgp-peers
neighbor x.x.5.25 peer-group ibgp-peers
distance bgp 200 200 200
no auto-summary
!
ip classless
!
#########################################
Do we need "ip route x.x.0.0 255.255.224.0 Null0" statement in above config?
I divided our network into different subnets in order to make load sharing
work,
however I couldn't make redundancy work.
If one link goes down traffic will not switch to the other link. How can I
make redundancy work?
Am I missing some configurations?
I appreciate if somebody can help me to configure routers in this regard.
thanks in advance,
Ganbold
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