In this topology, I have two Alcatel-Lucent’s Service Router 7750 which is peering with internal BGP on local networks and both of them also peering with external BGP to the upstream router. In this case, an upstream router used for internet connection.
Assumption
UPSTREAM Router:
UPSTREAM Router AS Number: 54321
UPSTREAM Router IP Address for eBGP peering with SR1: 202.202.202.1/30
UPSTREAM Router IP Address for eBGP peering with SR1: 202.202.202.4/30
SR1-7750:
SR1-7750 AS Number: 12345
SR1-7750 IP Address for eBGP: 202.202.202.2/30
SR1-7750 IP Address for iBGP: 101.101.101.1/30
SR2-7750:
SR2-7750 AS Number: 12345
SR2-7750 IP Address for eBGP: 202.202.202.5/30
SR2-7750 IP Address for iBGP: 101.101.101.2/30
1. Create Autonomous System (AS) Number
SR1:
A:SR1-7750# configure router autonomous-system 12345
SR2:
A:SR2-7750# configure router autonomous-system 12345
2. Preparing the interface
Create interface for eBGP peering to UPSTREAM Router on port 2/1/1
SR1:
A:SR1-7750# configure router interface "EXTERNAL-BGP"
A:SR1-7750>config>router>if# address 202.202.202.2/30
A:SR1-7750>config>router>if# port 2/1/1
SR2:
A:SR2-7750# configure router interface "EXTERNAL-BGP"
A:SR2-7750>config>router>if# address 202.202.202.5/30
A:SR2-7750>config>router>if# port 2/1/1
Create interface for iBGP peering with both of 7750-SR on port 2/2/1
SR1:
A:SR1-7750# configure router interface "INTERNAL-BGP"
A:SR1-7750>config>router>if# address 101.101.101.1/30
A:SR1-7750>config>router>if# port 2/2/1
SR2:
A:SR2-7750# configure router interface "INTERNAL-BGP"
A:SR2-7750>config>router>if# address 101.101.101.2/30
A:SR2-7750>config>router>if# port 2/2/1
A:SR1-7750>config>router# info
---------------------------------------------------
#--------------------------------------------------
echo "IP Configuration"
#--------------------------------------------------
interface "EXTERNAL-BGP"
address 202.202.202.2/30
port 2/1/1
exit
interface "INTERNAL-BGP"
address 101.101.101.1/30
port 2/2/1
autonomous-system 12345
router-id 1.1.1.1
#--------------------------------------------------
3. Configure internal BGP between SR1 and SR2
SR1:
A:SR1-7750# configure router bgp group "ibgp"
A:SR1-7750>config>router>bgp>group# description "INTERNAL-BGP"
A:SR1-7750>config>router>bgp>group# family ipv4
A:SR1-7750>config>router>bgp>group# next-hop-self
A:SR1-7750>config>router>bgp>group# type internal
A:SR1-7750>config>router>bgp>group# peer-as 56257
A:SR1-7750>config>router>bgp>group# neighbor 101.101.101.2
A:SR1-7750>config>router>bgp>group>neighbor# peer-as 12345
SR2:
A:SR2-7750# configure router bgp group "ibgp"
A:SR2-7750>config>router>bgp>group# description "INTERNAL-BGP"
A:SR2-7750>config>router>bgp>group# family ipv4
A:SR2-7750>config>router>bgp>group# next-hop-self
A:SR2-7750>config>router>bgp>group# type internal
A:SR2-7750>config>router>bgp>group# peer-as 12345
A:SR2-7750>config>router>bgp>group# neighbor 101.101.101.1
A:SR2-7750>config>router>bgp>group>neighbor# peer-as 12345
4. Configure external BGP for peering with upstream router
SR1:
A:SR1-7750>config>router>bgp# group "ebgp"
A:SR1-7750>config>router>bgp>group# description "EXTERNAL-BGP"
A:SR1-7750>config>router>bgp>group# family ipv4 vpn-ipv4 l2-vpn mvpn-ipv4
A:SR1-7750>config>router>bgp>group# connect-retry 5
A:SR1-7750>config>router>bgp>group# type external
A:SR1-7750>config>router>bgp>group# neighbor 202.202.202.1
A:SR1-7750>config>router>bgp>group>neighbor# peer-as 54321
SR2:
A:SR2-7750>config>router>bgp# group "ebgp"
A:SR2-7750>config>router>bgp>group# description "EXTERNAL-BGP"
A:SR2-7750>config>router>bgp>group# family ipv4 vpn-ipv4 l2-vpn mvpn-ipv4
A:SR2-7750>config>router>bgp>group# connect-retry 5
A:SR2-7750>config>router>bgp>group# type external
A:SR2-7750>config>router>bgp>group# neighbor 202.202.202.4
A:SR2-7750>config>router>bgp>group>neighbor# peer-as 54321
5. Check BGP peering, make sure BGP state was ESTABLISH and each router receive routing table from next hop router
A:SR1-7750# show router bgp summary
===============================================================================
BGP Router ID:1.1.1.1 AS:12345 Local AS:12345
===============================================================================
BGP Admin State : Up BGP Oper State : Up
Total Peer Groups : 2 Total Peers : 2
Total BGP Paths : 68881 Total Path Memory : 11616056
Total IPv4 Remote Rts : 387104 Total IPv4 Rem. Active Rts : 387104
Total IPv6 Remote Rts : 0 Total IPv6 Rem. Active Rts : 0
Total Supressed Rts : 0 Total Hist. Rts : 0
Total Decay Rts : 0
Total VPN Peer Groups : 0 Total VPN Peers : 0
Total VPN Local Rts : 0
Total VPN-IPv4 Rem. Rts : 0 Total VPN-IPv4 Rem. Act. Rts: 0
Total VPN-IPv6 Rem. Rts : 0 Total VPN-IPv6 Rem. Act. Rts: 0
Total L2-VPN Rem. Rts : 0 Total L2VPN Rem. Act. Rts : 0
Total VPN Supp. Rts : 0 Total VPN Hist. Rts : 0
Total VPN Decay Rts : 0
Total MVPN-IPv4 Rem Rts : 0 Total MVPN-IPv4 Rem Act Rts : 0
Total MDT-SAFI Rem Rts : 0 Total MDT-SAFI Rem Act Rts : 0
===============================================================================
BGP Summary
===============================================================================
Neighbor
AS PktRcvd InQ Up/Down State|Rcv/Act/Sent (Addr Family)
PktSent OutQ
-------------------------------------------------------------------------------
101.101.101.2
12345 102955 0 17d22h13m 1/1/387103 (IPv4)
2995299 0
202.202.202.1
54321 3622510 0 35d13h16m 387103/387103/16 (IPv4)
103119 0
===============================================================================
A:SR1-7750# show router bgp neighbor
===============================================================================
BGP Neighbor
===============================================================================
-------------------------------------------------------------------------------
Peer : 101.101.101.2
Group : ibgp
-------------------------------------------------------------------------------
Peer AS : 12345 Peer Port : 50867
Peer Address : 101.101.101.2
Local AS : 54321 Local Port : 179
Local Address : 101.101.101.1
Peer Type : Internal
State : Established Last State : Established
Last Event : recvKeepAlive
Last Error : Cease
Local Family : IPv4
Remote Family : IPv4
Hold Time : 90 Keep Alive : 30
Active Hold Time : 90 Active Keep Alive : 30
Cluster Id : None
Preference : 170 Num of Update Flaps : 211
Recd. Paths : 17
IPv4 Recd. Prefixes : 1 IPv4 Active Prefixes : 1
IPv4 Suppressed Pfxs : 0 VPN-IPv4 Suppr. Pfxs : 0
VPN-IPv4 Recd. Pfxs : 0 VPN-IPv4 Active Pfxs : 0
Mc IPv4 Recd. Pfxs. : 0 Mc IPv4 Active Pfxs. : 0
Mc IPv4 Suppr. Pfxs : 0 IPv6 Suppressed Pfxs : 0
IPv6 Recd. Prefixes : 0 IPv6 Active Prefixes : 0
VPN-IPv6 Recd. Pfxs : 0 VPN-IPv6 Active Pfxs : 0
VPN-IPv6 Suppr. Pfxs : 0 L2-VPN Suppr. Pfxs : 0
L2-VPN Recd. Pfxs : 0 L2-VPN Active Pfxs : 0
MVPN-IPv4 Suppr. Pfxs: 0 MVPN-IPv4 Recd. Pfxs : 0
MVPN-IPv4 Active Pfxs: 0 MDT-SAFI Suppr. Pfxs : 0
MDT-SAFI Recd. Pfxs : 0 MDT-SAFI Active Pfxs : 0
Input Queue : 0 Output Queue : 0
i/p Messages : 102967 o/p Messages : 2995531
i/p Octets : 996432 o/p Octets : 149572028
i/p Updates : 498 o/p Updates : 2893036
TTL Security : Disabled Min TTL Value : n/a
Graceful Restart : Disabled Stale Routes Time : n/a
Advertise Inactive : Disabled Peer Tracking : Disabled
Advertise Label : None
Auth key chain : n/a
Bfd Enabled : Disabled L2 VPN Cisco Interop : Disabled
Local Capability : RtRefresh MPBGP 4byte ASN
Remote Capability : RtRefresh MPBGP 4byte ASN
Import Policy : None Specified / Inherited
Export Policy : None Specified / Inherited
-------------------------------------------------------------------------------
Peer : 202.202.202.1
Group : ebgp
-------------------------------------------------------------------------------
Peer AS : 54321 Peer Port : 179
Peer Address : 202.202.202.1
Local AS : 12345 Local Port : 50316
Local Address : 202.202.202.2
Peer Type : External
State : Established Last State : Active
Last Event : recvKeepAlive
Last Error : Cease
Local Family : IPv4 VPN-IPv4 L2-VPN MVPN-IPv4
Remote Family : IPv4
Hold Time : 90 Keep Alive : 30
Active Hold Time : 90 Active Keep Alive : 30
Cluster Id : None
Preference : 170 Num of Update Flaps : 9460526
Recd. Paths : 2512764
IPv4 Recd. Prefixes : 387067 IPv4 Active Prefixes : 387067
IPv4 Suppressed Pfxs : 0 VPN-IPv4 Suppr. Pfxs : 0
VPN-IPv4 Recd. Pfxs : 0 VPN-IPv4 Active Pfxs : 0
Mc IPv4 Recd. Pfxs. : 0 Mc IPv4 Active Pfxs. : 0
Mc IPv4 Suppr. Pfxs : 0 IPv6 Suppressed Pfxs : 0
IPv6 Recd. Prefixes : 0 IPv6 Active Prefixes : 0
VPN-IPv6 Recd. Pfxs : 0 VPN-IPv6 Active Pfxs : 0
VPN-IPv6 Suppr. Pfxs : 0 L2-VPN Suppr. Pfxs : 0
L2-VPN Recd. Pfxs : 0 L2-VPN Active Pfxs : 0
MVPN-IPv4 Suppr. Pfxs: 0 MVPN-IPv4 Recd. Pfxs : 0
MVPN-IPv4 Active Pfxs: 0 MDT-SAFI Suppr. Pfxs : 0
MDT-SAFI Recd. Pfxs : 0 MDT-SAFI Active Pfxs : 0
Input Queue : 0 Output Queue : 0
i/p Messages : 3622840 o/p Messages : 103132
i/p Octets : 352757880 o/p Octets : 1968148
i/p Updates : 3511304 o/p Updates : 425
TTL Security : Disabled Min TTL Value : n/a
Graceful Restart : Disabled Stale Routes Time : n/a
Advertise Inactive : Disabled Peer Tracking : Disabled
Advertise Label : None
Auth key chain : n/a
Bfd Enabled : Disabled L2 VPN Cisco Interop : Disabled
Local Capability : RtRefresh MPBGP 4byte ASN
Remote Capability : RtRefresh MPBGP 4byte ASN
Import Policy : None Specified / Inherited
Export Policy : test
-------------------------------------------------------------------------------
Neighbors : 2
===============================================================================
