load balancing in OSPF with 7 E1s

[spremkumar]

Hi all

Right now we have 7 E1 links between 2 of our locatins in which we are able to load balance with 6 of our links and use them.

When i try to make use of the 7th link i m unable to make use of that 7th link.

we tried by removing other link and adding the 7th then it wrks fine.but wehn i add the remd link the same status its not at all utilized.

is ther any specification or anything becoz which i m denied to use the 7th link.

i m doing per packet load sharing at present.

any help on this regards will be helpful.

regds

prem

[liviu.gheorghe · Accepted solution]

Prior to IOS ver 12.3 the maximum number of equal cost links you could load balance is 6.

Starting with IOS ver 12.3 the maximum number of equal cost links you could load balance hast changed to 16.

Cheers

[spremkumar]

hi

thx for u r reply ,i m using 12.2.18S1 code at present in my 7513 on both the sides .

i am running this to have my network MPLS ready,can i achieve the load balancing part with some other workouts retaining the same ios which i cant distrub becoz of mpls compliance.

regds

prem

[ruwhite]

Try setting your maximum-paths to 8 under router ospf--that should work, since there was an intermediate step in between 6 paths and 16 of 8, and it should have been around 12.1.

:-)

Russ.W

[spremkumar]

Hi russ

thx for the reply.i will give a try on wht u mentioned.

one more query though i m using 6 Links with load balancing enabled when i trace any ip behind the other location i m getting displayed only 3 links.

why its not showing the other 3 links i.e.,6 in total ?ideally it shuld show all the 6 right since all of them r being used .is it becoz of any limitation or the particular trace being placed between only 3 links??

regds

prem

[ruwhite]

Where are you tracerouting from? If it's the router itself, then it should use all the available links (the links shown in the routing table). Of course, since process switching relies on the routing table to keep track of which interface to use next, another packet process switch between your trace packets will cause the counter to skip, which means you'll see a skipped link on the trace.

If you're cef switching (sourcing the traceroute from some other device), then you should really only see one link in use when trace routing through the router. You might see several links used on the way back, since you will have replies coming back from different devices along the trace, each with a different IP address, but on the way out, the router should consistently choose one path.

:-)

Russ.W

[spremkumar]

hi russ

i hve tried tracing from router and normally i m getting only 3 paths since default probe count value is 3.when i increased the same to 10 and timeout to 5 i am able to get 5 Links instead of 6.

regarding load balancing we tried to put max-paths to 8 but still no traffic in my 7th link.

regds

prem

[cnu_nivas]

Hi ,

OSPF will not supoort maximum-paths 7 but you can have option upto 8 links ,OSPF support maximum-paths 6 and u can't use 7 th link in OSPF load balancing.

Regards,

Srinivas.S

[cnu_nivas]

OSPF will not supoort maximum-paths 7 but you can have option upto maximum-paths 8, OSPF support maximum-paths 6 and u can't use 7 th link in OSPF load balancing of prior IOS ver 12.3.

regards,

Srinivas.S