In this lab, we are going to use IBGP and EBGP for peer relationship. HSRP will provide us redundant gateways as if active fail; standby will take the place of active HSRP. Read requirements carefully.
Requiremnents:
- Configure IP Addresses as per diagram. Configure one loop back address 5.5.5.5 on Internet router.
- Configure HSRP on both HSRP1 (Active) and HSRP2 (standby). Track interface between HSRP1 & ISP1 and HSRP2 & ISP2 for fail-over.
- Without doing any configuration related to propagating any network to neighbors, redistribution, static routing. Make sure network 100.10.10.0 should communicate to network 5.5.5.5.
- Packet coming from internet router to LAN should take preffered path and ensure that secondary path route becomes less preferred as compared to preferred path
- Demonstrate internet router path for 100.10.10.0 network by using show ip bgp 100.10.10.0 command and by traceroute.
| ! HSRP1 Configuration interface Serial0/0 ip address 16.16.16.1 255.255.255.0 no shut interface FastEthernet0/1 ip address 100.10.10.1 255.255.255.0 no shut standby 10 ip 100.10.10.100 standby 10 priority 150 standby 10 preempt delay minimum 70 standby 10 track Serial0/0 60 router bgp 50 network 100.10.10.0 mask 255.255.255.0 neighbor 16.16.16.2 remote-as 80 neighbor 100.10.10.2 remote-as 50 neighbor 100.10.10.2 next-hop-self ! HSRP2 Configuration interface FastEthernet0/0 ip address 100.10.10.2 255.255.255.0 no shut standby 10 ip 100.10.10.100 standby 10 priority 120 standby 10 preempt standby 10 track Serial0/0 interface Serial0/0 ip address 22.22.22.1 255.255.255.0 no shut router bgp 50 network 100.10.10.0 mask 255.255.255.0 neighbor 22.22.22.2 remote-as 200 neighbor 22.22.22.2 route-map AS-Path-Append out neighbor 100.10.10.1 remote-as 50 neighbor 100.10.10.1 next-hop-self access-list 10 permit 100.10.10.0 route-map AS-Path-Append permit 10 match ip address 10 set as-path prepend 50 ! ISP1 Configuration interface Serial0/0 ip address 16.16.16.2 255.255.255.0 no shut interface Serial0/1 ip address 160.16.16.1 255.255.255.0 no shut router bgp 80 neighbor 16.16.16.1 remote-as 50 neighbor 160.16.16.2 remote-as 500 ! ISP2 Configuration interface Serial0/0 ip address 22.22.22.2 255.255.255.0 no shut interface Serial0/1 ip address 210.16.16.2 255.255.255.0 no shut router bgp 200 neighbor 22.22.22.1 remote-as 50 neighbor 210.16.16.1 remote-as 500 ! Internet Configuration interface Loopback0 ip address 5.5.5.5 255.255.255.0 interface Serial0/0 ip address 160.16.16.2 255.255.255.0 no shut interface Serial0/1 ip address 210.16.16.1 255.255.255.0 no shut router bgp 500 network 5.5.5.0 mask 255.255.255.0 neighbor 160.16.16.1 remote-as 80 neighbor 210.16.16.2 remote-as 200 | Configuration Explanation 70 seconds delay so that BGP routes get into routing table. Tracking serial 0/0 so that if it gets failed; HSRP shift role to standby router when communicating to neighbor 22.22.22.2 and sending information out to it; BGP should consult route-map name AS-PAth-Append Access list 10 permitting route. (We use this in route map) Here comes route map route map will match all ip addresses in access list 10 if match found then it will prepend its AS-Path attribute with 50. This will let outside world (AS) perceive that this route is the longest one as compared some other actually equal route. |
BGP network verification Internet#show ip bgp 100.10.10.0 BGP routing table entry for 100.10.10.0/24, version 3 Paths: (2 available, best #2, table Default-IP-Routing-Table) Flag: 0x820 Advertised to update-groups: 1 200 50 50 [Look here you see that actual AS-Path should have (200 50) but due to route map and AS-Path prepend applied on HSRP2 router; Router AS path is showing that this route will go from 3 AS] 210.16.16.2 from 210.16.16.2 (210.16.16.2) Origin IGP, localpref 100, valid, external 80 50 [Here there are 2 AS in AS-Path; hence preferable] 160.16.16.1 from 160.16.16.1 (160.16.16.1) Origin IGP, localpref 100, valid, external, best | Trace route verification When both HSRP routers are running cool and tracked interfaces have no issues at all. Following is the trace route. pc1V10[1]> tracert 5.5.5.5 traceroute to 5.5.5.5, 64 hops max, press Ctrl+C to stop 1 100.10.10.1 70.000 ms 62.000 ms 40.000 ms 2 16.16.16.2 80.000 ms 40.000 ms 36.000 ms 3 *160.16.16.2 107.000 ms (Please note that as 5.5.5.5 is a loopback thats why traceroute just stops here) Anyhow see the path. PAckets are taking HSRP1 path. |
Now I have shutdown HSRP and ISP1 interface so that HSRP2 should take Active role. Now see results
| Internet#show ip bgp 100.10.10.0 BGP routing table entry for 100.10.10.0/24, version 4 Paths: (1 available, best #1, table Default-IP-Routing-Table) Flag: 0x820 Advertised to update-groups: 1 200 50 50 210.16.16.2 from 210.16.16.2 (210.16.16.2) Origin IGP, localpref 100, valid, external, best Please note that now previously preferred route is not there | pc1V10[1]> tracert 5.5.5.5 traceroute to 5.5.5.5, 64 hops max, press Ctrl+C to stop 1 100.10.10.2 60.000 ms 30.000 ms 30.000 ms 2 22.22.22.2 60.000 ms 40.000 ms 40.000 ms 3 *210.16.16.1 72.000 ms (Please note that as 5.5.5.5 is a loopback thats why traceroute just stops here) Anyhow see the path. PAckets are taking HSRP2 path. |
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