Routing

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  • 1.  Selecting Routing instances

    Posted 06-02-2011 21:05

    Hi all,

     

    I would like to know, if i divided in some routing-table-instances my forwarding table when any paquet's comes, how is the search inside the instances or forwarding table. the forwarding table is divided inside ?? someone can explain more better this process.

     

    Regards,

     

     



  • 2.  RE: Selecting Routing instances

     
    Posted 06-02-2011 23:56

    Hi,

     

    When you create multiple routing-instance, this would create separate RIB and FIB table for each of the routing-instance.

    And as you would have included interface(s) inside a routing-instance configs, corresponding forwarding table would be consulted upon an recepit of an incoming packet over that interface.

     

     

    Below is one of the example for VRF routing-instance named as VPNA

     

    suryak@PE# run show bgp summary
    Groups: 2 Peers: 2 Down peers: 0
    Table          Tot Paths  Act Paths Suppressed    History Damp State    Pending
    inet.0                 0          0          0          0          0          0
    bgp.l3vpn.0          101        101          0          0          0          0
    Peer                     AS      InPkt     OutPkt    OutQ   Flaps Last Up/Dwn State|#Active/Received/Accepted/Damped...
    2.2.2.2                 100         32         36       0       0       10:44 Establ
      bgp.l3vpn.0: 101/101/101/0
      VPNA.inet.0: 101/101/101/0
    172.169.1.2             300         18         24       0       0        7:31 Establ
      VPNA.inet.0: 100/100/100/0

    [edit]
    suryak@PE# run show route table VPNA

    VPNA.inet.0: 203 destinations, 203 routes (203 active, 0 holddown, 0 hidden)
    + = Active Route, - = Last Active, * = Both

    172.168.1.0/30     *[BGP/170] 00:07:43, localpref 100, from 2.2.2.2
                          AS path: I
                        > to 10.8.4.1 via xe-2/0/0.0, label-switched-path PE1-PE2
    172.169.1.0/30     *[Direct/0] 00:07:52
                        > via xe-2/0/3.0
    172.169.1.1/32     *[Local/0] 00:11:45
                          Local via xe-2/0/3.0
    200.10.1.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.2.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.3.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.4.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.5.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.6.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.7.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.8.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.9.0/24      *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.10.0/24     *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.11.0/24     *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.12.0/24     *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.13.0/24     *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.14.0/24     *[BGP/170] 00:07:43, localpref 100
                          AS path: 300 I
                        > to 172.169.1.2 via xe-2/0/3.0
    200.10.15.0/24     *[BGP/170] 00:07:43, localpref 100
                                           
    [edit]
    suryak@PE# run show route forwarding-table table VPNA
    Routing table: VPNA.inet
    Internet:
    Destination        Type RtRef Next hop           Type Index NhRef Netif
    default            perm     0                    rjct   586     1
    0.0.0.0/32         perm     0                    dscd   584     1
    172.168.1.0/30     user     0                    indr 2097318     3
                                  10.8.4.1          Push 302656   776     1 xe-2/0/0.0
    172.169.1.0/30     intf     0                    rslv   523     1 xe-2/0/3.0
    172.169.1.0/32     dest     0 172.169.1.0        recv   521     1 xe-2/0/3.0
    172.169.1.1/32     intf     0 172.169.1.1        locl   522     2
    172.169.1.1/32     dest     0 172.169.1.1        locl   522     2
    172.169.1.2/32     dest     1 0:10:94:0:0:1      ucst   532   104 xe-2/0/3.0
    172.169.1.3/32     dest     0 172.169.1.3        bcst   519     1 xe-2/0/3.0
    200.10.1.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.2.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.3.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.4.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.5.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.6.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.7.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.8.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0
    200.10.9.0/24      user     0 172.169.1.2        ucst   532   104 xe-2/0/3.0

     

    Regards

    Surya Prakash



  • 3.  RE: Selecting Routing instances

    Posted 06-03-2011 04:18

    Hi,

     

    (i want to know the behavior of search an incoming packet)

    Ecxatly, that's the point, when some incoming packet's are consulted, how in the routing table knows which instance preferred and after in on that instance what happen when the Network isn't there(logest match), is moved to other instances  or dropped the packet???

     

     

     

    Regards,



  • 4.  RE: Selecting Routing instances
    Best Answer

    Posted 06-03-2011 04:46

    Two cases exist:

    1. If traffic arrives on interface that's assigned to a routing-instance, then only FIB of that routing-instance will be used. If no mach is found, the packet is dropped.

    2. If traffic mach firewall filter rule that indicate which routing-instance to use,  then only FIB of that routing-instance will be used. If no mach is found, the packet is dropped.