8 - BGP Extra

Question 1

What is Local Preference?
Internal/external?
Default value?

Answer 1

Defaults to 100
internal only
Used to prefer one exit over another

Question 2

What is Administrative Distance used for?

Answer 2

Used to separate routes learnt by more than one protocol. Lowest distance is then installed in table

Question 3

Administrative Distance: Defaults

Local, iBGP and eBGP

Answer 3

Local: 200
iBGP: 200
eBGP: 20

Question 4

Exchange Point

Answer 4

High speed network or ethernet switch that links major providers

Question 5

Why are Internet Exchange points relatively cheaper than individual peering?

In terms of number of circuits to buy

Answer 5

Participants only need to buy one whole circuit each (unlike peering to many etc)

Question 6

Internet Exchange Point benefits

(QoS,RTTs and economy)

Answer 6

QoS considerations locally not an issue
RTTs are usually sub 10ms
Local internet economy grows

Question 7

What does each participant need to peer at an IXP

Answer 7

Each participant needs BGP and an AS number.
Configure eBGP with other participants