The Border Gateway Protocol (BGP) uses different tables to resolve protocol next-hop for different applications. In a normal BGP application like IPv4, the prefix is learned in the default table inet.0. BGP will try to resolve its protocol next-hop in the table inet.3 first; if fails, it will resolve in the table inet.0. However, in L3VPN and L2VPN applications, BGP will resolve its protocol next-hop in the table inet.3 only. This article explains which route table is used by BGP to resolve the protocol next-hop for NG-MVPN (v4 and v6), and gives two case examples.
This article explains which route table is used by BGP to resolve protocol next-hop for NG-MVPN (v4 and v6).
Case 1: BGP protocol next-hop exists in both table inet.0 and inet.3.
<----Route resolution is kept by default.
> show configuration routing-options resolution | display inheritance no-comments {MASTER}
<----As a BGP protocol next-hop, 10.233.32.17 exists in both table inet.0 and inet.3.
> show route 10.233.32.17/32 exact inet.0: 526772 destinations, 1047867 routes (526770 active, 0 holddown, 2 hidden) + = Active Route, - = Last Active, * = Both 10.233.32.17/32 *[IS-IS/18] 29w5d 12:50:45, metric 2400 to 10.55.36.148 via ge-0/0/0.0 > to 10.55.36.150 via ge-1/0/0.0 inet.3: 5663 destinations, 6709 routes (1044 active, 0 holddown, 5663 hidden) + = Active Route, - = Last Active, * = Both 10.233.32.17/32 *[LDP/9] 29w5d 12:50:02, metric 2400 to 10.55.36.148 via ge-0/0/0.0, label-switched-path LSP:a2b > to 10.55.36.150 via ge-1/0/0.0, label-switched-path LSP:a2c to 10.55.36.150 via ge-1/0/0.0, label-switched-path LSP:a2b to 10.55.36.148 via ge-0/0/0.0, label-switched-path LSP:a2c {MASTER}
<----BGP uses table inet.3 to resolve protocol next-hop 10.233.32.17 for NG-MVPN prefix.
> show route table bgp.mvpn.0 match-prefix 7:10.233.38.59:5006:4788:32:10.0.194.198:32:239.192.100.230/240 extensive bgp.mvpn.0: 833 destinations, 1666 routes (833 active, 0 holddown, 0 hidden) 7:10.233.38.59:5006:4788:32:10.0.194.198:32:239.192.100.230/240 (2 entries, 0 announced) *BGP Preference: 170/-101 Next hop type: Indirect Address: 0x119725f8 Next-hop reference count: 1544 Source: 10.233.32.17 Protocol next hop: 10.233.32.17 Indirect next hop: 2 no-forward State: <active int="" ext=""> Local AS: 4788 Peer AS: 4788 Age: 30w1d 20:46:03 Metric2: 2400 Task: BGP_4788.10.233.32.17+52531 AS path: I (Originator) Cluster list: 10.233.32.16 AS path: Originator ID: 10.233.32.17 Communities: target:10.233.38.59:6 Import Accepted Localpref: 100 Router ID: 10.233.32.17 Secondary Tables: TM_IPTV_HSBB.mvpn.0 Indirect next hops: 1 Protocol next hop: 10.233.32.17 Metric: 2400 Indirect next hop: 2 no-forward Indirect path forwarding next hops: 4 Next hop type: Router Next hop: 10.55.36.148 via ge-0/0/0.0 weight 0x1 Next hop: 10.55.36.150 via ge-1/0/0.0 weight 0x1 Next hop: 10.55.36.150 via ge-1/0/0.0 weight 0x4001 Next hop: 10.55.36.148 via ge-0/0/0.0 weight 0x4001 10.233.32.17/32 Originating RIB: inet.3 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Metric: 2400 Node path count: 1 Forwarding nexthops: 4 Nexthop: 10.55.36.148 via ge-0/0/0.0 Nexthop: 10.55.36.150 via ge-1/0/0.0 Nexthop: 10.55.36.150 via ge-1/0/0.0 Nexthop: 10.55.36.148 via ge-0/0/0.0
Case 2: BGP protocol next-hop exists in table inet.0 only.
<----As a BGP protocol next-hop, 202.165.59.11 exists in table inet.0 only.
> show route 202.165.59.11 exact inet.0: 58 destinations, 58 routes (57 active, 0 holddown, 1 hidden) + = Active Route, - = Last Active, * = Both 202.165.59.11/32 *[OSPF/10] 00:35:32, metric 20 > to 192.168.2.1 via xe-0/0/0.0 {MASTER}
> show route table bgp.mvpn-inet6.0 match-prefix 6:7473:1501:7473:128:2001:1:1::1:128:ff08::1/432 extensive bgp.mvpn-inet6.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden) 6:7473:1501:7473:128:2001:1:1::1:128:ff08::1/432 (1 entry, 0 announced) *BGP Preference: 170/-101 Next hop type: Indirect Address: 0xce96ba8 Next-hop reference count: 2 Source: 202.165.59.11 Protocol next hop: 202.165.59.11 Indirect next hop: 2 no-forward State: <active int="" ext=""> Local AS: 7473 Peer AS: 7473 Age: 34:49 Metric2: 20 Task: BGP_7473.202.165.59.11+55670 AS path: I (Originator) Cluster list: 202.165.59.11 Originator ID: 202.164.59.11 Communities: target:202.164.59.21:526 Import Accepted Localpref: 100 Router ID: 202.164.59.11 Secondary Tables: vrf-1501.mvpn-inet6.0 Indirect next hops: 1 Protocol next hop: 202.165.59.11 Metric: 20 Indirect next hop: 2 no-forward Indirect path forwarding next hops: 1 Next hop type: Router Next hop: 192.168.2.1 via xe-0/0/0.0 202.165.59.11/32 Originating RIB: inet.0 <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Metric: 20 Node path count: 1 Forwarding nexthops: 1 Nexthop: 192.168.2.1 via xe-0/0/0.0 {MASTER}
Regarding NG-MVPN (v4 and v6), BGP will try to resolve its protocol next-hop in the table inet.3 first. If this fails, it will resolve in the table inet.0.