08-12-2024 10:04 PM
ospf table-map using distance for TE cisco document;
can i use metric(cost) instead of distance?
please suggest me
thanks
kindly see attached
Solved! Go to Solution.
08-12-2024 11:37 PM
Hello @sanhtethlaing ,
the route-map foo in your example sets the Admin distance for different types of routes or using more specific match conditions.
setting the metric would be an action that interfers with OSPF link state database and SPF algorythm for this reason I think it is not supported.
Edit:
as you can see in the following configuration guide the table map is intended to be used only to modify AD of routes
So as I have written above you cannot set the metric using a table map .
Hope to help
Giuseppe
08-13-2024 02:25 AM - edited 08-13-2024 02:28 AM
Hello @sanhtethlaing ,
>> may i know any suggestion, to do traffic engineering on nexus 9k, i currently two 9k as primary and secondary, but routing was going via both switches
by default OSPF supports ECMP = Equal Cost Multi Path and devices perform flow based load balancing.
if you want to have a primary / backup the easy move is to increase OSPF cost on both sides of link between Nexus2 (the intended secondary) and the peer device(s).
Take in account also the possible different settings on the autoreference bandwidth that is 40 Gbps in NXOS and 100 Mbps in traditional IOS , IOS XE.
The command in IOS XE is ip ospf cost <value> in interface mode .
You can check current OSPF costs using the following on all involved devices
show ip ospf interface
You need to use the same command both on peer and on Nexus2.
Other possible options are available depending on the type of OSPF routes and if you are using an OSPF multi area design (as opposed to single area).
If there are not security devices in the path like transparent FWs or IPS you may be fine to stay with ECMP.
Also FWs in routed mode can be in the path and they need to see both directions of each flow to properly work.
Another possible reason for having Primary / Secondary routing are the use of network analyzers.
Hope to help
Giuseppe
08-12-2024 11:37 PM
Hello @sanhtethlaing ,
the route-map foo in your example sets the Admin distance for different types of routes or using more specific match conditions.
setting the metric would be an action that interfers with OSPF link state database and SPF algorythm for this reason I think it is not supported.
Edit:
as you can see in the following configuration guide the table map is intended to be used only to modify AD of routes
So as I have written above you cannot set the metric using a table map .
Hope to help
Giuseppe
08-12-2024 11:44 PM
I will check this in lab
MHM
08-12-2024 11:47 PM
thanks for your reply
may i know any suggestion, to do traffic engineering on nexus 9k, i currently two 9k as primary and secondary, but routing was going via both switches
so let me know best practice to manipulate route traffic
thanks again
08-13-2024 01:15 AM
the Metric (cost) can not use as @Giuseppe Larosa mention
""may i know any suggestion, to do traffic engineering on nexus 9k, i currently two 9k as primary and secondary, but routing was going via both switches""
table-map is inject route into RIB in NSK, you need to prefer path in Peer connect to two NSK not use table-map
MHM
08-13-2024 02:25 AM - edited 08-13-2024 02:28 AM
Hello @sanhtethlaing ,
>> may i know any suggestion, to do traffic engineering on nexus 9k, i currently two 9k as primary and secondary, but routing was going via both switches
by default OSPF supports ECMP = Equal Cost Multi Path and devices perform flow based load balancing.
if you want to have a primary / backup the easy move is to increase OSPF cost on both sides of link between Nexus2 (the intended secondary) and the peer device(s).
Take in account also the possible different settings on the autoreference bandwidth that is 40 Gbps in NXOS and 100 Mbps in traditional IOS , IOS XE.
The command in IOS XE is ip ospf cost <value> in interface mode .
You can check current OSPF costs using the following on all involved devices
show ip ospf interface
You need to use the same command both on peer and on Nexus2.
Other possible options are available depending on the type of OSPF routes and if you are using an OSPF multi area design (as opposed to single area).
If there are not security devices in the path like transparent FWs or IPS you may be fine to stay with ECMP.
Also FWs in routed mode can be in the path and they need to see both directions of each flow to properly work.
Another possible reason for having Primary / Secondary routing are the use of network analyzers.
Hope to help
Giuseppe
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