BGP Configuration and Route Analysis

Questions and Answers

What command would be used to ensure the community value appears in the BGP routing table?

set community 64512:600 (correct)

router bgp 64512

network 10.10.10.0 mask 255.255.255.0

route-map COMM deny 10

What does the community value '64512:600' indicate in the route-map COMM?

The originating router's autonomous system

A filter preventing route advertisements

The highest preference for the route

A grouping to which this route belongs (correct)

In the output of 'show ip bgp 10.10.10.0', what does the term 'localpref 100' imply?

The route is preferred but not the best

This is the default local preference value (correct)

The route has been rejected by the filter

The route was learned via an IGP

What could be a reason the community value is not found in the BGP routing table despite being set?

The route-map COMM is not applied correctly Signup and view all the answers

How does the command 'neighbor 10.1.1.1 remote-as 1' affect BGP routing?

It specifies a remote AS for the BGP neighbor Signup and view all the answers

R2#show run | begin bgp

router bgp 64512 neighbor 10.1.1.1 remote-as 1 network 10.10.10.0 mask 255.255.255.0 route-map COMM

route-map COMM permit 10 set community 64512:600

R2#show ip bgp 10.10.10. 0 BGP routing table entry for 10.10 10.0/24，version 1320 Paths: (1 available, best #1) Local 0.0.0.0 from 0.0.0.0 (1.1.1.1) Origin IGP, metric 0, localpref100, weight 32768, valid, sourced, local, best Community 64512:600 Refer to the exhibit. The eBGP neighbor 10.1.1.1 of router R2 receives and installs the prefix,but the community value is not found in the BGP routing table. How must this issue be resolved?

Community values are nontransitive and R2 is an eBGP peer, configure R2 to send community Signup and view all the answers

Study Notes

BGP Configuration for Router R2

Router R2 operates under BGP Autonomous System Number (ASN) 64512.
It configures a neighbor with IP address 10.1.1.1 belonging to ASN 1.
The command network 10.10.10.0 mask 255.255.255.0 route-map COMM is used to advertise route 10.10.10.0 with a specified subnet mask and route-map.

Route-Map Configuration

A route-map named COMM allows traffic and assigns a community value using set community 64512:600.
This configuration permits matching routes with the highest priority.

BGP Routing Table Entry

The routing table has an entry for the subnet 10.10.10.0/24 with version number 1320.
The best path is sourced from local IP 0.0.0.0 with various attributes:
- Origin marked as IGP
- Metric set to 0
- Local preference of 100
- Weight of 32768
The path is valid, sourced, local, and identified as the best route.
It is tagged with the community value 64512:600.

Issue with Community Value

The eBGP neighbor (10.1.1.1) successfully receives and installs the prefix into its table.
The community value 64512:600, however, is not appearing in the BGP routing table as expected.

Resolution Steps for the Community Value Issue

Confirm the BGP configurations on both peers to ensure the community values are being recognized and correctly propagated.
Check local policies or filters that might be excluding certain community values from being accepted or advertised.
Utilize debug commands to analyze the BGP updates and advertisements to diagnose where the community assignment might be failing.

Description

This quiz covers the basics of BGP (Border Gateway Protocol) configurations and the analysis of routing tables. It explores neighbor relationships, community settings, and BGP routing entries using specific examples. Test your understanding of BGP concepts and commands.