You are troubleshooting a Layer 3 VPN issue. The VPN has been passing traffic successfully for some time, but now it is reported that traffic is no longer flowing.
You look into the bgp.l3vpn.0 table and see newly hidden routes.
What would be the cause of this problem?
A. The LSP used to connect the PE routers is down.
B. The connection from the PE to the customer is down.
C. The BGP routes received from the customer are no longer reachable.
D. The family inet-vpn parameter was deleted from the BGP configuration of the PE router.
|
Download Printable PDF. VALID exam to help you PASS. |
 |
A. LSP down so VPN routes will be hidden because BGP cannot resolve next-hop for these routes in tablet inet.3
Zakhar is right..The right answer is A.
The bgp routes can hidden due to one of the below reasons.
Routes can be hidden for the following reasons:
An import policy rejects the route.
The next hop cannot be resolved using the current indirect next hop resolution rule. Because routing protocols such as internal BGP (IBGP) can send routing information about indirectly connected routes, Junos OS relies on routes from intra-AS routing protocols (OSPF, IS-IS, RIP, and static) to resolve the best directly connected next hop. The Routing Engine performs route resolution to determine the best directly connected next hop and installs the route to the Packet Forwarding Engine.
A damping policy suppresses the route.
1) The AS path contains illegal or invalid confederation attributes.
2) The next hop address is the address of the local routing device.
3) The AS path contains illegal or invalid transitive attributes.
4) The AS path is empty. This only applies to EBGP. For IBGP, an empty AS path is normal.
5) The AS path contains a zero.
6) The next hop address is a multicast address.
7) The next hop address is an IPv6 link-local address.
8) The route prefix or the route next hop is a martian address.
9) The LDP (Label Distribution Protocol) session fails. The received routes are not installed in the routing table until the peer router reestablishes the LDP session.
A is the answer. removal of inet-vpn causes the local router to not receive the route at all, not just mark it as Hidden. if the next-hop of any route in bgp.l3vpn.0 cant be resolved (to the destination) using an LSP in inet.3 (RSVP/LDP), the route becomes hidden.
Hi, Are you sure about the answer ?
zakhar is right.
Zakhar is Right.The right answer is A.
Routes can be hidden for the following reasons:
An import policy rejects the route.
The next hop cannot be resolved using the current indirect next hop resolution rule. Because routing protocols such as internal BGP (IBGP) can send routing information about indirectly connected routes, Junos OS relies on routes from intra-AS routing protocols (OSPF, IS-IS, RIP, and static) to resolve the best directly connected next hop. The Routing Engine performs route resolution to determine the best directly connected next hop and installs the route to the Packet Forwarding Engine.
1) A damping policy suppresses the route.
2) The AS path contains illegal or invalid confederation attributes.
3) The next hop address is the address of the local routing device.
4) The AS path contains illegal or invalid transitive attributes.
5) The AS path is empty. This only applies to EBGP. For IBGP, an empty AS path is normal.
6) The AS path contains a zero.
7) The next hop address is a multicast address.
8) The next hop address is an IPv6 link-local address.
9) The route prefix or the route next hop is a martian address.
10) The LDP (Label Distribution Protocol) session fails. The received routes are not installed in the routing table until the peer router reestablishes the LDP session.