В GNS была собрана схема работы L3VPN между Juniper (M/T) и Cisco 7200. Проблема в том что после обмена маршрутами по MP-BGP между железками, они попадают в нужные vrf, но ping из vrf так и не проходит. Данные настройки применялись на реальном железе, но результат не меняется.
Vrf vpna используется для получения маршрутов от оператора, по верх которых поднимается gre и строится свой vpn? т.е. vrf - vpnb.

version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname Denver
!
ip cef
no ip domain lookup
!
!
ip vrf vpna
rd 65000:1
route-target export 65000:10
route-target import 65000:10
!
ip vrf vpnb
rd 65000:3
route-target export 65000:11
route-target import 65000:11
!
ip ips po max-events 100
mpls label protocol ldp
no ftp-server write-enable
!
!
interface Tunnel1
ip address 40.0.0.2 255.255.255.252
ip router isis
mpls label protocol ldp
tag-switching ip
tunnel source 10.0.0.2
tunnel destination 10.0.0.1
tunnel vrf vpna
!
interface Loopback0
ip address 30.0.0.1 255.255.255.255
ip router isis
!
interface FastEthernet0/0
ip vrf forwarding vpna
ip address 10.0.0.2 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet0/1
ip vrf forwarding vpnb
ip address 31.0.0.1 255.255.255.0
duplex auto
speed auto
!
router isis
net 49.0001.0001.0002.00
!
router bgp 65000
no synchronization
bgp log-neighbor-changes
neighbor 20.0.0.1 remote-as 65000
neighbor 20.0.0.1 update-source Loopback0
neighbor 20.0.0.1 soft-reconfiguration inbound
no auto-summary
!
address-family vpnv4
neighbor 20.0.0.1 activate
neighbor 20.0.0.1 send-community extended
exit-address-family
!
address-family ipv4 vrf vpnb
redistribute connected
no auto-summary
no synchronization
exit-address-family
!
address-family ipv4 vrf vpna
neighbor 10.0.0.1 remote-as 101
neighbor 10.0.0.1 local-as 102
neighbor 10.0.0.1 update-source FastEthernet0/0
neighbor 10.0.0.1 activate
no auto-summary
no synchronization
exit-address-family
!
ip classless

end
----------------------------------
root> show configuration
## Last commit: 2011-12-09 08:57:08 UTC by root
version 9.3R1.7;
-----
interfaces {
    em0 {
        unit 0 {
            family inet {
                address 10.0.0.1/30;
            }
        }
    }
    em1 {
        unit 0 {
            family inet {
                address 21.0.0.1/24;
            }
        }
    }
    gre {
        unit 0 {
            tunnel {
                source 10.0.0.1;
                destination 10.0.0.2;
                routing-instance {
                    destination vpna;
                }
            }
            family inet {
                address 40.0.0.1/30;
            }
            family iso;
            family mpls;
        }
    }
    lo0 {
        unit 0 {
            family inet {
                address 20.0.0.1/32;
            }
            family iso {
                address 49.0001.0001.0001.00;
            }
        }
    }
}
protocols {
    mpls {
        interface gre.0;
    }
    bgp {
        group vpnb {
            type internal;
            family inet {
                unicast;
            }
            family inet-vpn {
                unicast;
            }
            local-as 65000;
            neighbor 30.0.0.1;
        }
    }
    isis {
        interface gre.0;
        interface lo0.0;
    }
    ldp {
        interface gre.0;
    }
}
policy-options {
    policy-statement export_vpna {
        term 1 {
            from protocol [ direct bgp ];
            then {
                community add com_vpna;
                accept;
            }
        }
        term 2 {
            then reject;
        }
    }
    policy-statement export_vpnb {
        term 1 {
            from protocol [ bgp direct ];
            then {
                community add com_vpnb;
                accept;
            }
        }
        term 2 {
            then reject;
        }
    }
    policy-statement import_vpna {
        term 1 {
            from {
                protocol bgp;
                community com_vpna;
            }
            then accept;
        }
        term 2 {
            then reject;
        }
    }
    policy-statement import_vpnb {
        term 1 {
            from {
                protocol bgp;
                community com_vpnb;
            }
            then accept;
        }
        term 2 {
            then reject;
        }
    }
    community com_vpna members target:65000:10;
    community com_vpnb members target:65000:11;
}
routing-instances {
    vpna {
        instance-type vrf;
        interface em0.0;
        route-distinguisher 65000:2;
        vrf-import import_vpna;
        vrf-export export_vpna;
        vrf-table-label;
        protocols {
            bgp {
                group vpna {
                    type external;
                    local-address 10.0.0.1;
                    peer-as 102;
                    local-as 101;
                    neighbor 10.0.0.2;
                }
            }
        }
    }
    vpnb {
        instance-type vrf;
        interface em1.0;
        route-distinguisher 65000:3;
        vrf-import import_vpnb;
        vrf-export export_vpnb;
        vrf-table-label;
    }
}

root> show route table vpnb.inet.0 detail

vpnb.inet.0: 3 destinations, 3 routes (3 active, 0 holddown, 0 hidden)
21.0.0.0/24 (1 entry, 1 announced)
        *Direct Preference: 0
                Next hop type: Interface
                Next-hop reference count: 1
                Next hop: via em1.0, selected
                State: <Active Int>
                Age: 1:18:37
                Task: IF
                Announcement bits (1): 1-BGP RT Background
                AS path: I

21.0.0.1/32 (1 entry, 0 announced)
        *Local  Preference: 0
                Next hop type: Local
                Next-hop reference count: 4
                Interface: em1.0
                State: <Active NoReadvrt Int>
                Age: 1:18:37
                Task: IF
                AS path: I

31.0.0.0/24 (1 entry, 1 announced)
        *BGP    Preference: 170/-101
                Route Distinguisher: 65000:3
                Next hop type: Indirect
                Next-hop reference count: 3
                Source: 30.0.0.1
                Next hop type: Router, Next hop index: 575
                Next hop: via gre.0, selected
                Label operation: Push 18
                Protocol next hop: 30.0.0.1
                Push 18
                Indirect next hop: 8c3e000 131070
                State: <Secondary Active Int Ext>
                Peer AS: 65000
                Age: 46:53      Metric: 0       Metric2: 1
                Task: BGP_65000_65000.30.0.0.1+14880
                Announcement bits (1): 0-KRT
                AS path: ?
                Communities: target:65000:11
                Accepted
                VPN Label: 18
                Localpref: 100
                Router ID: 30.0.0.1
                Primary Routing Table bgp.l3vpn.0

Denver#show ip route vrf vpnb

     21.0.0.0/24 is subnetted, 1 subnets
B       21.0.0.0 [200/0] via 20.0.0.1, 00:47:53
     31.0.0.0/24 is subnetted, 1 subnets
C       31.0.0.0 is directly connected, FastEthernet0/1

Если запустить ping на june
root> ping 31.0.0.1 routing-instance vpnb source 21.0.0.1
PING 31.0.0.1 (31.0.0.1): 56 data bytes

, а на cisco включить debug ip icmp, то она выдает следующее:

*Dec  9 13:49:51.283: ICMP: echo reply sent, src 31.0.0.1, dst 21.0.0.1
*Dec  9 13:49:52.407: ICMP: echo reply sent, src 31.0.0.1, dst 21.0.0.1
*Dec  9 13:49:53.439: ICMP: echo reply sent, src 31.0.0.1, dst 21.0.0.1