OSPF hop count

[inaeemcisco]

Feature of OSPF is : it has unlimited hop count, upto how many hops a packet will traverse and what does unlimited means?

[e.ciollaro]

Hi,

OSPF is a link state protocol,  not a distance vector protocol. It doesn't use hop count as a metric (like RIP) neither as loop prevention mechanism like EIGRP).

OSPF scaling is limited by the protocol characteristics and depends on many factors, see the following:

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/7039-1.html

http://www.ciscopress.com/articles/article.asp?p=1763921&seqNum=6 )

Bye,

enrico

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

As already noted by Enrico, OSPF doesn't use hops as a metric, so there's no logical hop count limitation.  However, remember IP packets have a hop count limit (TTL) so although OSPF isn't counting them, the packet itself will.  Also OSPF does have scalability issues so you'll bump into practical limitations making "unlimited" not really "unlimited".