This lab is same as previous Lab " HSRP Redundancy in Multi-homed ISPs - BGP AS-Path prepending" in many aspects but there were some short commings left in previous labs. Previously if our immediate route failed between our HSRP divice and ISP; we can track that but what if; Any of the link between source and destination fail. Previous configuration let our HSRP device working as Active device and we will face severe packet losses and communication errors. Here in this lab we will track ip addresses instead of connected interfaces so that if that route become unavailable then Active HSRP shift its role to standby ISP.
Let's do our lab.
Let's do our lab.
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 ip address between HSRP1 & internet for fail-over.
- Configure IBGP in a way that HSRP1 should not sent BGP update to its neighbor HSRP2 and vice versa
- 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
- For verification use following command and compare results with previous Lab " HSRP Redundancy in Multi-homed ISPs - BGP AS-Path prepending" results. Follow these commands and take help from previous lab
- Show ip route ; Show ip bgp ip-address ; traceroute or tracert ; ping ; show standby (for HSRP) ; show standby brief ; show ip bgp summary ; show ip bgp ; debug ip bgp etc
| ! 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 1 decrement 60 track 1 ip route 5.5.5.0 255.255.255.0 reachability 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 neighbor 100.10.10.2 transport connection-mode passive ! 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 neighbor 100.10.10.1 transport connection-mode passive 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 track 1 (mentioned in next command). If 5.5.5.0 route fail to come into route table of HSRP1 ; HSRP1 shift role to standby router (HSRP router) by decrementing its current priority from 150 to 90 track to check if 5.5.5.0 is reachable This command let HSRP2 not sending updates to its specified neighbor when communicating to neighbor 22.22.22.2 and sending information out to it; BGP should consult route-map name AS-PAth-Append This command let HSRP2 not sending updates to its specified neighbor 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. |
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