Junos OS

Expand all | Collapse all

no ip route-cache in JUNOS?

Jump to Best Answer
  • 1.  no ip route-cache in JUNOS?

    Posted 06-14-2020 21:44



    Is there any compatible configuration command in JUNOS as following command in Cisco IOS.



    lab-R2(config)#interface GigabitEthernet 0/1
    lab-R2(config-if)#no ip route-cache



    Mostly it is a describe of interface behaviour to disallow any route cache to be placed or stored on corelated single interface. Any help or clue would be appreciated. Or perhaps any thought that is has similiarity with ARP cache? Thanks.

  • 2.  RE: no ip route-cache in JUNOS?
    Best Answer

    Posted 06-14-2020 22:16



    Short answer is no.

    Long answer is Cisco "ip route-cache" feature is not supported in JUNOS and no equivalent feature exists.

    You can ignore this particular command when translating CSCO IOS config to JUNOS.




  • 3.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 22:22



    Could you help me with the understanding if this below command refers to the cached entries in FT ? 

    show route forwarding-table extensive | match cache

    Also, isn't this knob similar to arp cache at interface level ?




  • 4.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 22:35



    I don't see any "cache" entries in FT on real MX2020, JUNOS 20.2 beta:


    user@router> show isis adjacency 
    15 Jun 2020 01:28:15 EDT
    Interface             System         L State        Hold (secs) SNPA
    ae0.0                 PTX-2 		 2 Up           19
    et-19/0/0.0           Core-NCS 		 2 Up          	23
    xe-13/0/0.0           P-3 		 2 Up           26
    user@router> show route forwarding-table extensive | grep cach    
    15 Jun 2020 01:28:19 EDT

    user@router> show route forwarding-table summary
    15 Jun 2020 01:33:46 EDT
    Routing table: default.inet
    user: 9 routes
    perm: 5 routes
    intf: 9 routes
    dest: 16 routes



    Please specify the platform and JUNOS release. If You are doing this on vMX it is possible that You see flow cache entries which is an entirely different feature.





  • 5.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 22:49

    Hi Alex, 


    Thanks for answering that, I just wanted to understand the use case of FLAG cached in the output.

    Link: https://www.juniper.net/documentation/en_US/junos/topics/reference/command-summary/show-route-forwarding-table-mpls-ex-series.html#show-route-forwarding-table



  • 6.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 22:56



    It may be related to this feature https://www.juniper.net/documentation/en_US/junos/topics/topic-map/mcast-forwarding-cache.html


    Without multicast, there are no "cached" JUNOS FT entries as far as I can see.




  • 7.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 23:10



    Thanks for the quick answer and the link, it now clears my doubt. 

    Cached refers to multicast forwarding cache entries as per documentation you shared and not the cached ip routes.



  • 8.  RE: no ip route-cache in JUNOS?

    Posted 06-14-2020 23:18

    Thanks, Alex. So it has no convert to JUNOS anyway.

    I also found the clue about multicast route cache and cache on forwarding table. But none of them are the same.

  • 9.  RE: no ip route-cache in JUNOS?

    Posted 06-15-2020 19:11

    That relates to 'fast switching' which is what Cisco devices used before they introduced CEF.

    This is vendor specific, and doesn't apply to Junos.

    The Junos 'equivallent' (sort of) is separating the RE from the PFE to perform faster forwarding of frames and packets.