Possible for a CISCO network using EIGRP to communicate over a Juniper OSPF network

[tuckerrose]

For Clarity, I have a system that is currently running CISCO EIGRP and uses a CISCO OSPF backbone to communicate to remote sites that also run CISCO EIGRP, the backbone we communicate over is being changed out to Juniper OSPF. I am not familiar with Juniper in the slightest, and to the best of my knowledge even though EIGRP is open standard now, they do not support EIGRP

1) Is it possible to redistribute an EIGRP Cisco Net over Juniper OSPF?

2) Will I have to bite the bullet and swap my network over to OSPF?

3) Would I need any Juniper devices on the border of my network to talk?

[Giuseppe Larosa · Accepted solution]

Hello @tuckerrose 

1) Is it possible to redistribute an EIGRP Cisco Net over Juniper OSPF?

No, you should run OSPF on a Cisco device and redistribute EIGRP into OSPF on the cisco device then you can build an OSPF adjacency between the Cisco device and the Juniper router

2) Will I have to bite the bullet and swap my network over to OSPF?

This can be a reasonable option. You can migrate one branch office using it as a Proof of Concept or Pilot.

3) Would I need any Juniper devices on the border of my network to talk?

No you can run OSPF between Cisco devices and Juniper devices. Just be aware that in JUNOS the MTU is actually like in IOS XR IP size + 14 bytes   ( the 4 bytes of FCS are not counted) more L2 concept.

For tagged frames the MTU might become IP Size +14 + 4 byte 802.1Q on the Juniper side.

Hope to help

Giuseppe

[tuckerrose]

Thank you for your help, I appreciate it! I especially like the idea of adding in another CISCO device to redistribute  EIGRP to OSPF.

[Giuseppe Larosa]

Hello,

yes redistribution can only happen on a device that supports both protocols.

Just a note for the OSPF part: Juniper uses the dotted decimal notation for area-id so area 0 becomes 0.0.0.0 and area 1 0.0.0.1 on their side. This notation is supported also on Cisco routers

Hope to help

Giuseppe

[Georg Pauwen]

Hello,

on a side note, I am thinking it could also be possible to build a tunnel between the Cisco devices, and hence extend the EIGRP network across the Juniper backbone.

[Giuseppe Larosa]

Hello Georg,

Yes this could be an option but if there are many sites the number of p2p GRE tunnels could become high.

To overcome this scalability issue a DMVPN could be used if the routers have the correct feature sets or nowdays licenses

Hope to help

Giuseppe

[Georg Pauwen]

Indeed, DMVPN is what I was thinking of. That might even be a better option, since you can add security.