Thursday, June 15, 2017

Basic Border Gateway Protocol Interview Questions and Answers

1. Explain Border Gateway Protocol (BGP) ?
Border Gateway Protocol advertises, learns and chooses the best paths inside the global Internet. When two ISPs connect, they typically use BGP to exchange routing information. Enterprises also sometimes uses BGP to exchange routing information with ISPs, allowing the Enterprise routers to learn Internet routes. when we have multiple Internet connections and we want to influence some packets to take one path and some packets to take another we use BGP.

2. Can Routers on different subnet become BGP neighbors?
BGP does not require neighbors to be attached to the same subnet. Instead, BGP routers use a TCP connection between the routers to pass BGP messages allowing neighboring routers to be on the same or different subnet.

3. What TCP port number BGP use for connection?
BGP uses TCP port 179 for the connection.

4. Difference between eBGP and iBGP neighbor?
In iBGP, neighborship is formed between routers within the same AS (autonomous system) whereas in eBGP, neighborship is formed between routers within different AS.

5. What Administrative Distance BGP uses for iBGP & eBGP ?
AD for iBGP = 200, AD for eBGP = 20.

Read More Questions:
BGP Interview Questions Part1
BGP Interview Questions Part2
BGP Interview Questions Part3
BGP Interview Questions Part4

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