Note!
CE3 and CE4 use BACKDOOR link (should be used by CE routers as a secondary path).
Use the configuration from the previous lab (lab 181).
Use the configuration from the previous lab (lab 181).
Topology
Pic2. MPLS Topology 2
You are about to advertise subnets connected to CE3 (R5). The subnets are the two loopbacks:
Loopback1 - 192.168.5.1/27
Loopback2 - 192.168.5.33/27
Based on the previous lab (Lab 181), you should fully understand what a non-standard BGP Cost Community achieves. Consider what can happen when CE3 (R5) advertises its Loopback 1 subnet (192.168.5.0/27) and then it becomes inaccessible (shutdown). Explain what two racing conditions can occur and what they can cause in the given design. List all potential solutions: their pros and cons. Then, proceed to the the tasks below.
! Here is your homework, you must start digging deep.
! Do your Google search on the topic.
! It is imperative that you are able to find information on this,
! and understand the concept. I will help you only when you are
! DESPARATE
! Geeks are sometimes busy you know ...
Task 1
In CE3 (R5) and CE4 (R4) advertise loopback1 and loopback 2 into EIGRP.
Task 2
Provide a solution preventing the potential loop that can occur when CE3's Loopback is shutdown (subnet inaccessible). The solution can allow a stale information to be propagated for a short moment but should not rely on changing the default hop count limitation.
Solution
Task 1
In CE3 (R5) and CE4 (R4) advertise loopback1 and loopback 2 into EIGRP.
CE3 and CE4 Config:
!
router eigrp 100
network 172.16.0.0
network 192.168.5.0
no auto-summary
Task 2
Provide a solution preventing the potential loop that can occur when CE3's Loopback is shutdown (subnet inaccessible). The solution can allow a stale information to be propagated for a short moment but should not rely on changing the default hop count limitation.
PE1 (R1) Config:
!
route-map FILTER_WHEN_IT_GETS_BACK permit 10
set extcommunity soo 100:5
!
interface FastEthernet0/0.15
encapsulation dot1Q 15
ip vrf forwarding A
ip vrf sitemap FILTER_WHEN_IT_GETS_BACK
ip address 172.16.15.1 255.255.255.0
!
PE2 (R3) Config:
!
route-map FILTER_WHEN_IT_GETS_BACK permit 10
set extcommunity soo 100:4
Loopback1 - 192.168.5.1/27
Loopback2 - 192.168.5.33/27
Based on the previous lab (Lab 181), you should fully understand what a non-standard BGP Cost Community achieves. Consider what can happen when CE3 (R5) advertises its Loopback 1 subnet (192.168.5.0/27) and then it becomes inaccessible (shutdown). Explain what two racing conditions can occur and what they can cause in the given design. List all potential solutions: their pros and cons. Then, proceed to the the tasks below.
! Here is your homework, you must start digging deep.
! Do your Google search on the topic.
! It is imperative that you are able to find information on this,
! and understand the concept. I will help you only when you are
! DESPARATE
! Geeks are sometimes busy you know ...
Task 1
In CE3 (R5) and CE4 (R4) advertise loopback1 and loopback 2 into EIGRP.
Task 2
Provide a solution preventing the potential loop that can occur when CE3's Loopback is shutdown (subnet inaccessible). The solution can allow a stale information to be propagated for a short moment but should not rely on changing the default hop count limitation.
Solution
Task 1
In CE3 (R5) and CE4 (R4) advertise loopback1 and loopback 2 into EIGRP.
CE3 and CE4 Config:
!
router eigrp 100
network 172.16.0.0
network 192.168.5.0
no auto-summary
!
Task 2
Provide a solution preventing the potential loop that can occur when CE3's Loopback is shutdown (subnet inaccessible). The solution can allow a stale information to be propagated for a short moment but should not rely on changing the default hop count limitation.
PE1 (R1) Config:
!
route-map FILTER_WHEN_IT_GETS_BACK permit 10
set extcommunity soo 100:5
!
interface FastEthernet0/0.15
encapsulation dot1Q 15
ip vrf forwarding A
ip vrf sitemap FILTER_WHEN_IT_GETS_BACK
ip address 172.16.15.1 255.255.255.0
!
PE2 (R3) Config:
!
route-map FILTER_WHEN_IT_GETS_BACK permit 10
set extcommunity soo 100:4
!
interface FastEthernet0/0.34
encapsulation dot1Q 34
ip vrf forwarding A
ip vrf sitemap FILTER_WHEN_IT_GETS_BACK
ip address 172.16.34.3 255.255.255.0
!
