OSPF configuration

[ssweehinlew]

I try to setup the simple OSPF connection between 2 switches. The setup was done and the protocol is running. When I do the tracertroute from workstation 172.21.6.1 to the next 2 hop of the IP 172.21.3.1, it cannot reach it. It stop at the gateway 172.21.6.254.  

Any items I miss out and does static route need to be added? 

SW1(config)#router ospf 1
SW1(config-router)#network 172.21.3.0 0.0.0.255 area 2
SW1(config-router)#network 1.1.1.0 0.0.0.255 area 2
SW1(config-router)#network 10.1.3.0 0.0.0.255 area 2

SW2(config)#router ospf 1
SW2(config-router)#network 172.21.6.0 0.0.0.255 area 2
SW2(config-router)#network 2.2.2.0 0.0.0.255 area 2
SW2(config-router)#network 172.21.3.0 0.0.0.255 area 2

[Jon Marshall]

Well your Juniper switch is not advertising the PC subnet to the Cisco switch.

Your OSPF neighborship is not coming up so there is no exchange of routes.

Jon

[ssweehinlew]

Hi,

Is the configuration correct?

SW1(config)#router ospf 1
SW1(config-router)#network 172.21.3.0 0.0.0.255 area 2
SW1(config-router)#network 1.1.1.0 0.0.0.255 area 2
SW1(config-router)#network 10.1.3.0 0.0.0.255 area 2

SW2(config)#router ospf 1
SW2(config-router)#network 172.21.6.0 0.0.0.255 area 2
SW2(config-router)#network 2.2.2.0 0.0.0.255 area 2
SW2(config-router)#network 172.21.3.0 0.0.0.255 area 2

[Bilal Nawaz]

Hello, Please try this configuration:

SW1 - CISCO:

conf t

!

router ospf 1

router-id 1.1.1.1

network 1.1.1.1 0.0.0.0 area 0

network 172.21.3.1 0.0.0.0 area 0

!

interface vlan 506

ip ospf network point-to-point

SW2 - Juniper:

}
protocols {
    ospf {

      area 0.0.0.0 {

         interface vlan.506 {
              interface-type p2p;

    }

         interface loopback0.0 {

               passive;

    }

        area 0.0.0.2 {

            interface vlan.702 {

                passive;

           }
        }
    }

hope this helps.

Bilal

EDIT: Please take out the static routes if you want to use a dynamic routing protocol.

[ssweehinlew]

It doesn't help even i set the interface type to p2p

[prajithtr_2]

Make MTU size of both routers(Both cisco and juniper)same.Mostly Stuck in neighbour forming in Exstart/Exchange state is due to MTU mismatch

Reference

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13684-12.html#neighbors

Regards

Prajith

[ssweehinlew]

What I supposed to see from the OSPF neighborship? It can find the neighbor ID 2.2.2.2

Cisco switch

---------------

Switch#sh ip ospf nei                       

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2         128   EXCHANGE/DR     00:00:39    172.21.3.2      Vlan506

[Bilal Nawaz]

Paste config output from cisco and juniper. You are meant to see FULL after successful neighborship

[ssweehinlew]

Attached is the configuration. Thank you for the help.

[Bilal Nawaz]

As everyone has been saying I think there could be an MTU problem. I'd like to verify this though.

On the juniper can you do this please...

show ospf interface vlan.506

On the cisco please do

show ip ospf interface vlan 506

Kindly post both outputs here.

[ssweehinlew]

Please refer to below:

Cisco

--------

Switch#show ip ospf interface vlan 506
Vlan506 is up, line protocol is up 
  Internet Address 172.21.3.1/24, Area 2 
  Process ID 10, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:02
  Supports Link-local Signaling (LLS)
  Index 3/3, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 1, Adjacent neighbor count is 0 
  Suppress hello for 0 neighbor(s)
Switch#

Juniper

-----------

root> show ospf interface detail  
Interface           State   Area            DR ID           BDR ID          Nbrs
lo0.0               DRother 0.0.0.2         0.0.0.0         0.0.0.0            0
  Type: LAN, Address: 2.2.2.2, Mask: 255.255.255.0, MTU: 65535, Cost: 0
  Adj count: 0, Passive
  Hello: 10, Dead: 40, ReXmit: 5, Not Stub
  Auth type: None
  Protection type: None
  Topology default (ID 0) -> Passive, Cost: 0
vlan.0              PtToPt  0.0.0.2         0.0.0.0         0.0.0.0            1
  Type: P2P, Address: 172.21.3.2, Mask: 255.255.255.0, MTU: 1500, Cost: 1
  Adj count: 0
  Hello: 10, Dead: 40, ReXmit: 5, Not Stub
  Auth type: None
  Protection type: None
  Topology default (ID 0) -> Cost: 1
vlan.702            Down    0.0.0.2         0.0.0.0         0.0.0.0            0
  Type: LAN, Address: 172.21.6.254, Mask: 255.255.255.0, MTU: 1500, Cost: 1
  Adj count: 0, Passive
  Hello: 10, Dead: 40, ReXmit: 5, Not Stub
  Auth type: None
  Protection type: None
  Topology default (ID 0) -> Passive, Cost: 1

[Bilal Nawaz]

OK that looks fine, what about when you do "show int vlan 506" on cisco.

[ssweehinlew]

The MTU size is 1504 bytes. Should I set it as 1500 bytes?

Switch#sh int vlan 506
Vlan506 is up, line protocol is down 
  Hardware is EtherSVI, address is 001f.6ce6.07c3 (bia 001f.6ce6.07c3)
  Internet address is 172.21.3.1/24
  MTU 1504 bytes, BW 1000000 Kbit, DLY 10 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 00:13:17, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     7 packets output, 448 bytes, 0 underruns
     0 output errors, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
Switch#

[prajithtr_2]

please try to change the MTU of juniper interface as 1504

Regards

prajith

[ssweehinlew]

The issue was resolved after I set mtu size for cisco switch to 1500. 

system mtu routing 1500

[Bilal Nawaz]

Was there a specific reason for setting the system routing mtu size to 1504, if there isn't, I'd suggest putting it back to default.

on Cisco do 

'no system mtu routing 1504'

I also noticed the SVI is 'up down' could you check what might be wrong there please

hopefully that should bring the OSPF up