Skip to main content

BGP

BGP is a path vector routing protocol. He care about how many AS path numbers to pass not routers that why path vector protocol. BGP uses TCP port 179. We need to advertise exact network at BGP if not we don't see any network. We shouldn't forget about TTL of BGP. eBGP TTL is 1 and iBGP TTL is 255.

BGP have 6 states:
1. Idle
    Process shutdown or waiting for next retry.

2. Connect
    Waiting for TCP connection to complete.

3. Active
    TCP conection ready, No BGP messages sent.

4. Opensent.
    Open message send.

5. Openconfirm
    Receive open message from neighbor.

6. Established
    Finish peering and start routing.

eBGP and iBGP is difference only two word, between and within.

eBGP AD 20.
iBGP AD 200.

Difference AS but want to advertise as a same AS use confederation.

Ref : Wikipedia, Cisco

Labels:

Comments

Post a Comment

Popular posts from this blog

Access-list at SVI

SVI (Switch Virtual Interfaces) We use the SVI for inter vlan routing. In this scenario I will configure the access list with SVI. In this scenario I want to permit vlan 10 network to vlan 50 Server farm. Vlan 10 and vlan 20 can communicate each other. First create vlan and then interface vlan#. Switch(config)#vlan 10 Switch(config)#interface vlan 10 Switch(config-if)#ip address 192.168.10.254 255.255.255.0 Switch(config)#vlan 20 Switch(config)#interface vlan 20 Switch(config-if)#ip address 192.168.20.254 255.255.255.0 Switch(config)#vlan 50 Switch(config)#interface vlan 50 Switch(config-if)#ip address 192.168.50.254 255.255.255.0 when we finish the vlan interface create make sure the switch port are belong to each vlan. Port to vlan assign configure is Switch(config)#interface g0/1 Switch(config-if)#switchport access vlan 10 Switch(config)#interface g0/2 Switch(config-if)#switchport access vlan 20 Switch(config)#int...
1 comment
Read more

OSPF Stub

The following restrictions apply to stub areas:     You cannot create a virtual link through a stub area.   A stub area cannot contain an AS boundary router.   You cannot configure the backbone as a stub area.   You cannot configure an area as both a stub area and an not-so-stubby area (NSSA). Ref : Juniper.net
Post a Comment
Read more

Why does OSPF need backbone area?

Why does OSPF require all traffic between non-backbone areas to pass through a backbone area (area 0)?   Because inter-area OSPF is distance vector, it is vulnerable to routing loops. It avoids loops by mandating a loop-free inter-area topology, in which traffic from one area can only reach another area through area 0. Ref : Jeff Doyle article at Network world http://www.networkworld.com/article/2348778/cisco-subnet/my-favorite-interview-question.html
Post a Comment
Read more