OSPF States
DOWN:-
=====
No hello packets have been received.
++check L2 Issues or is there any firewall IP 89 blocked ?
STUCK at Attempt
============
1.check neighbor id mis configuration
2.access-lists
3,Incorrect DLCI (if using frame relay)
STUCK at INIT:
=========
(means router has received hello packets.)
+check if 225.0.0.5 is blocked
+ping to neighbor address ping should be successful, otherwise problem with link.
+authentication should be enabled on both sides or mismatch
+pcaps to see if we are getting reply packets with dest add=our ip
STUCK at TWO/way:
=============
(received hello and also sent hello, bi-directional comm established)
its a default behavior if you observer from DR other
+make sure you check neighbor from DR
R1/R2/R3R4/R5 all area connected through switch
R1=DR(adjacency router=which exchanges only HELLO and LSA packets)
R2=BDR(adjacency router=which exchanges only HELLO and LSA packets)
R3/R4/R5=DROTHER (neighbor router=which exchanges only HELLO packets)
R1#sh ip ospf nei
R2-BDR
R3/R4/R5-DRother
R2-BDR
R3#sh ip ospf nei
R1-DR
R2-BDR
R4/R5------>TWOWAY<============expected behaviour
Stuck at EXTART/EXCHANGE:
==================
(DR/BDR election happens in this state)master sends First DBD packet)
R1(mtu=1500)===========(mtu=1450) R2
R1#sh ip ospf nei
EXCHANGE
R2#sh ip ospf nei
EXSTART
+MTU mismatch
resolution:ip ospf mtu-ignore
+check the neighbor id's #sh ip bgp neighbor
LOADING:-
=======
Link state adv(LSA) are exchanged by two neighbors which contains routes, topology database.
router now checks if there is any router which is not found, it sends LSR requesting all LSA's and other responds with LSU
FULL:-
====
all neighbor routers are in sync and established.
0 Response to "OSPF States"
Post a Comment