EBGP Flashcards
What type of routing protocol exchanges information with a single autonomous system?
Interior Gateway Protocol (IGP)
What are the main three IGPs?
RIP
OSPF
EIGRP
What type of protocol exchanges routing information for different autonomous systems? BGP is an example of this.
Exterior Gateway Protocols
What TCP port does EBGP use?
179
When BGP is running between routers in different autonomous systems
EBGP
When BGP is running between routers in the same autonomous system
IBGP
Each ISP has their own _____
AS number
What command starts the BGP routing process for AS 1?
router bgp 1
How many routing processes are allowed per router?
1
The AS number is a ____ bit integer in the range from 1 to 65,534.
16
Does BGP automatically discover neighbors?
No
What option in addition to the network command uses a classful approach to insert a major network into the BGP table?
no mask
What command allows you to display the BGP configuration?
show run | section bgp
What command allows you to configure the external neighbors for R1 and R2 in bgp configuration mode? R1 (AS 100) - 192.168.1.11 R2 (AS 200) - 192.168.2.11
neighbor 192.168.1.11 remote-as 100
neighbor 192.168.2.11 remote-as 200
What command gives you an overview of the BGP status?
show ip bgp summary
What command supplies additional information about BGP connections to neighbors?
show ip bgp neighbors
What command allows you to view the entire BGP table?
show ip bgp
What symbol does the router use to show the best path towards the destination if alternative paths exist?
>
When BGP runs between two peers in the same AS, what is it referred to as?
IBGP
What command can you use to know the hold time on the two BGP peers?
show ip bgp neighbors
What does a next hop of 0.0.0.0 mean in the show ip bgp command output?
The network is locally originated via the network command in BGP
Because BGP does not use a neighbor discovery process like many other routing protocols, it is essential that every peer is manually configured and reachable through what protocol and port number?
TCP port 179
Once a peer has been configured with the “neighbor remote-as” command, the local BGP speaker will attempt to transmit an _____ message to the remote peer.
OPEN
If the OPEN message is not blocked by existing firewall rules or other security mechanisms, the remote peer will respond with a _____ message and will continue to periodically exchange these messages with the local peer.
KEEPALIVE
A BGP speaker will consider a peer dead if what kind of messages are not received within a period of time specified by a hold timer?
KEEPALIVE
What type of messages are used by BGP to exchange routing information between peers?
UPDATE
What kind of routes do UPDATE messages contain?
advertised and withdrawn
_____ routes are those which are no longer considered feasible.
Withdrawn
What command allows you to view statistics regarding the number of BGP messages, such as UPDATE messages, in the output?
show ip bgp neighbors
Router 1 has an AS number of 101. In the output of the “show ip bgp summary” command, the peer lists an AS number of 201. What does this signify in regards to what protocol is being used?
eBGP Different AS numbers = eBGP peers
Which two components are used to identify a neighbor in a BGP configuration?
- autonomous system number
- version number
- router ID
- subnet mask
- IP address
autonomous system number
IP address
