The goal we are trying to achieve, R5 is the sender for the 224.1.1.1 multicast group and R7 and R8 have joined 224.1.1.1 as receivers. After we configure the core, CEs and PE-CE connectivity, when R5 pings 224.1.1.1 there should be responses from both R7 and R8.
Multicast VPN, if you have never played with it before, is daunting to get working. The reason why is the provider runs it's own multicast infrastructure and the customer runs it's own multicast infrastructure. The customer could just use GRE tunneling techniques, P2P or DMVPN and achieve multicast reachability that way. MPLS L3 VPN can be used to route multicast traffic.
There are 5 major sections to get this working.
1. Configuring the SP core on the P and PE routers
2. Configuring the PEs for the MDT
3. Configuring PE-CE connections to be multicast aware
4. Configuring the Customers equipment to support to multicast
5. Test reachability
---------------------Configuring the SP core on the P and PE routers---------------------
The multicast transport is PIM encapsulated in the core.
R1 - Provider core router
ip multicast-routing distributed
!
interface Loopback0
ip pim sparse-mode
!
interface GigabitEthernet1.12
ip pim sparse-mode
!
interface GigabitEthernet1.13
ip pim sparse-mode
R1#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.1.3.1 GigabitEthernet1.13 v2/S 1 30 1 10.1.3.3
10.1.2.1 GigabitEthernet1.12 v2/S 1 30 1 10.1.2.2
172.16.100.1 Loopback0 v2/S 0 30 1 172.16.100.1
R1#sh ip pim neighbor | b Address
Address Prio/Mode
10.1.3.3 GigabitEthernet1.13 04:02:48/00:01:41 v2 1 / DR S P G
10.1.2.2 GigabitEthernet1.12 04:02:19/00:01:23 v2 1 / DR S P G
R2 - Provider core router
ip multicast-routing distributed
!
interface GigabitEthernet1.12
ip pim sparse-mode
!
interface GigabitEthernet1.24
ip pim sparse-mode
R2#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.1.2.2 GigabitEthernet1.12 v2/S 1 30 1 10.1.2.2
10.2.4.2 GigabitEthernet1.24 v2/S 1 30 1 10.2.4.4
R2#sh ip pim neighbor | b Address
Address Prio/Mode
10.1.2.1 GigabitEthernet1.12 04:03:44/00:01:34 v2 1 / S P G
10.2.4.4 GigabitEthernet1.24 03:36:17/00:01:28 v2 1 / DR S P G
R3 - Provider Edge router
ip multicast-routing distributed
!
interface Loopback0
ip pim sparse-mode
!
interface GigabitEthernet1.13
ip pim sparse-mode
R3#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.1.3.3 GigabitEthernet1.13 v2/S 1 30 1 10.1.3.3
172.16.100.3 Loopback0 v2/S 0 30 1 172.16.100.3
R3#sh ip pim neighbor | b Address
Address Prio/Mode
10.1.3.1 GigabitEthernet1.13 04:04:48/00:01:27 v2 1 / S P G
R4 - Provider Edge router
ip multicast-routing distributed
!
interface Loopback0
ip pim sparse-mode
!
interface GigabitEthernet1.24
ip pim sparse-mode
R4#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.2.4.4 GigabitEthernet1.24 v2/S 1 30 1 10.2.4.4
172.16.100.4 Loopback0 v2/S 0 30 1 172.16.100.4
R4#sh ip pim neighbor | b Address
Address Prio/Mode
10.2.4.2 GigabitEthernet1.24 03:37:49/00:01:30 v2 1 / S P G
---------------------Configuring PE-CE connections to be multicast aware---------------------
R3
ip multicast-routing vrf MCAST distributed
!
interface GigabitEthernet1.35
vrf forwarding MCAST
!
ip pim vrf MCAST rp-address 172.16.100.5
R3#sh ip pim vrf MCAST interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.3.5.3 GigabitEthernet1.35 v2/S 1 30 1 10.3.5.3
172.16.100.3 Tunnel0 v2/S 1 30 1 172.16.100.4
R3#sh ip pim vrf MCAST neighbor | b Address
Address Prio/Mode
10.3.5.5 GigabitEthernet1.35 04:10:48/00:01:40 v2 0 / S P G
172.16.100.4 Tunnel0 02:13:10/00:01:29 v2 1 / DR S P G
R3#sh ip pim vrf MCAST rp mapping
Group(s): 224.0.0.0/4, Static
RP: 172.16.100.5 (?)
R4
ip multicast-routing vrf MCAST distributed
!
interface GigabitEthernet1.48
vrf forwarding MCAST
!
interface GigabitEthernet1.47
vrf forwarding MCAST
!
ip pim vrf MCAST rp-address 172.16.100.5
R4#sh ip pim vrf MCAST interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
10.4.8.4 GigabitEthernet1.48 v2/S 1 30 1 10.4.8.4
172.16.100.4 Tunnel0 v2/S 1 30 1 172.16.100.4
10.4.7.4 GigabitEthernet1.47 v2/S 1 30 1 10.4.7.4
R4#sh ip pim vrf MCAST neighbor | b Address
Address Prio/Mode
10.4.8.8 GigabitEthernet1.48 04:12:07/00:01:22 v2 0 / S P G
172.16.100.3 Tunnel0 02:14:06/00:01:32 v2 1 / S P G
10.4.7.7 GigabitEthernet1.47 02:00:00/00:01:19 v2 0 / S P G
R4#sh ip pim vrf MCAST rp mapping
Group(s): 224.0.0.0/4, Static
RP: 172.16.100.5 (?)
---------------------Configuring the Customers equipment to support to multicast---------------------
R5
ip multicast-routing distributed
!
interface Loopback0
ip pim sparse-mode
!
interface GigabitEthernet1.35
ip pim dr-priority 0
ip pim sparse-mode
!
ip pim rp-address 172.16.100.5
R8
ip multicast-routing distributed
!
interface G1.48
ip pim dr-priority 0
ip pim sparse-mode
ip igmp join-group 224.1.1.1
!
ip pim rp-address 172.16.100.5
The "dr-priority 0" command is used on any link between 2 PIM neighbors where the PIM neighbor that is forwarding away from the RP has become the DR. The DR should always be in the forwarding direction towards the RP. If that is not the case, issue can occur.
The "dr-priority 0" command is used on any link between 2 PIM neighbors where the PIM neighbor that is forwarding away from the RP has become the DR. The DR should always be in the forwarding direction towards the RP. If that is not the case, issue can occur.
R8#sh ip pim rp map
Group(s): 224.0.0.0/4, Static
RP: 172.16.100.5 (?)
R7
ip multicast-routing distributed
!
interface G1.47
ip pim dr-priority 0
ip pim sparse-mode
ip igmp join-group 224.1.1.1
!
ip pim rp-address 172.16.100.5
R7#sh ip pim rp mapping
Group(s): 224.0.0.0/4, Static
RP: 172.16.100.5 (?)
---------------------Configuring the PEs for the IPv4 MDT---------------------
This builds the multicast distribution trees between the PEs and in this case, the RR. Once completed, R3 (172.16.100.3, 232.0.0.1) and R4(172.16.100.4, 232.0.0.1) should both be visible in the "ip mroute" table. These connections are the global MRIB and show all the multicast endpoints the provider can send traffic to. R1 is the route reflector, so nothing significant shows up. R3 and R4 are the PEs, looking at them we can see the "Z" indicating a multicast tunnel.
This builds the multicast distribution trees between the PEs and in this case, the RR. Once completed, R3 (172.16.100.3, 232.0.0.1) and R4(172.16.100.4, 232.0.0.1) should both be visible in the "ip mroute" table. These connections are the global MRIB and show all the multicast endpoints the provider can send traffic to. R1 is the route reflector, so nothing significant shows up. R3 and R4 are the PEs, looking at them we can see the "Z" indicating a multicast tunnel.
R1 - BGP Route Reflector
router bgp 1
address-family ipv4 mdt
neighbor MCAST route-reflector-client
neighbor 172.16.100.3 activate
neighbor 172.16.100.4 activate
neighbor 172.16.100.13 activate
neighbor 172.16.100.14 activate
R1#sh bgp ipv4 mdt all | b Network
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1
*>i 172.16.100.3/32 172.16.100.3 0 100 0 ?
*>i 172.16.100.4/32 172.16.100.4 0 100 0 ?
R1#sh ip mroute | b \(
(*, 232.0.0.1), 02:08:30/00:03:13, RP 172.16.100.1, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
GigabitEthernet1.13, Forward/Sparse, 02:08:21/00:03:13
(172.16.100.3, 232.0.0.1), 02:08:17/00:01:35, flags: T
Incoming interface: GigabitEthernet1.13, RPF nbr 10.1.3.3
Outgoing interface list:
GigabitEthernet1.12, Forward/Sparse, 02:08:17/00:03:08
(172.16.100.4, 232.0.0.1), 02:08:28/00:02:20, flags: T
Incoming interface: GigabitEthernet1.12, RPF nbr 10.1.2.2
Outgoing interface list:
GigabitEthernet1.13, Forward/Sparse, 02:08:21/00:03:15
(*, 224.0.1.40), 02:08:43/00:02:14, RP 172.16.100.1, flags: SJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
GigabitEthernet1.13, Forward/Sparse, 02:08:36/00:02:40
R3 - PE
router bgp 1
address-family ipv4 mdt
neighbor 172.16.100.1 activate
neighbor 172.16.100.1 send-community both
R3#sh bgp ipv4 mdt all | b Network
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf MCAST)
*> 172.16.100.3/32 0.0.0.0 0 ?
*>i 172.16.100.4/32 172.16.100.4 0 100 0 ?
R3#sh ip mroute | b \(
(*, 232.0.0.1), 03:37:54/stopped, RP 172.16.100.1, flags: SJCFZ
Incoming interface: GigabitEthernet1.13, RPF nbr 10.1.3.1
Outgoing interface list:
MVRF MCAST, Forward/Sparse, 03:37:52/00:00:46
(172.16.100.4, 232.0.0.1), 02:07:16/00:01:18, flags: JTZ
Incoming interface: GigabitEthernet1.13, RPF nbr 10.1.3.1
Outgoing interface list:
MVRF MCAST, Forward/Sparse, 02:07:16/00:00:46
(172.16.100.3, 232.0.0.1), 03:37:54/00:03:25, flags: FT
Incoming interface: Loopback0, RPF nbr 0.0.0.0
Outgoing interface list:
GigabitEthernet1.13, Forward/Sparse, 02:07:16/00:03:06
(*, 224.0.1.40), 04:09:06/00:02:08, RP 172.16.100.1, flags: SJPCL
Incoming interface: GigabitEthernet1.13, RPF nbr 10.1.3.1
Outgoing interface list: Null
R3#sh ip pim vrf MCAST neighbor | b ^Neighbor
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.3.5.5 GigabitEthernet1.35 13:55:17/00:01:19 v2 0 / S P G
172.16.100.4 Tunnel0 11:57:39/00:01:40 v2 1 / DR S P G
This is the connection point between the provider and customer for vrf MCAST, showing that there is a PIM neighbor down to the customer and a tunnel built to the other PE or R4. The tunnel is a multipoint GRE tunnel, allowing many PEs to connect to many other PEs enabled for IPv4 MDT.
R3#show derived-config interface tunnel0
interface Tunnel0
ip unnumbered Loopback0
no ip redirects
ip mtu 1500
tunnel source Loopback0
tunnel mode gre multipoint
This output shows that the tunnel is in fact a GRE tunnel. We didn't configure this, this is automatically implemented when MP-BGP IPv4 MDT is enabled.
R3#sh ip pim vrf MCAST neighbor | b ^Neighbor
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.3.5.5 GigabitEthernet1.35 13:55:17/00:01:19 v2 0 / S P G
172.16.100.4 Tunnel0 11:57:39/00:01:40 v2 1 / DR S P G
This is the connection point between the provider and customer for vrf MCAST, showing that there is a PIM neighbor down to the customer and a tunnel built to the other PE or R4. The tunnel is a multipoint GRE tunnel, allowing many PEs to connect to many other PEs enabled for IPv4 MDT.
R3#show derived-config interface tunnel0
interface Tunnel0
ip unnumbered Loopback0
no ip redirects
ip mtu 1500
tunnel source Loopback0
tunnel mode gre multipoint
This output shows that the tunnel is in fact a GRE tunnel. We didn't configure this, this is automatically implemented when MP-BGP IPv4 MDT is enabled.
R4 - PE
router bgp 1
address-family ipv4 mdt
neighbor 172.16.100.1 activate
neighbor 172.16.100.1 send-community both
R4#sh bgp ipv4 mdt all | b Network
Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1:1 (default for vrf MCAST)
*>i 172.16.100.3/32 172.16.100.3 0 100 0 ?
*> 172.16.100.4/32 0.0.0.0 0 ?
R4#sh ip mroute | b \(
(*, 232.0.0.1), 03:38:43/stopped, RP 172.16.100.1, flags: SJCFZ
Incoming interface: GigabitEthernet1.24, RPF nbr 10.2.4.2
Outgoing interface list:
MVRF MCAST, Forward/Sparse, 03:38:42/stopped
(172.16.100.3, 232.0.0.1), 02:07:58/00:02:29, flags: JTZ
Incoming interface: GigabitEthernet1.24, RPF nbr 10.2.4.2
Outgoing interface list:
MVRF MCAST, Forward/Sparse, 02:07:58/stopped
(172.16.100.4, 232.0.0.1), 03:38:43/00:02:39, flags: FT
Incoming interface: Loopback0, RPF nbr 0.0.0.0
Outgoing interface list:
GigabitEthernet1.24, Forward/Sparse, 02:08:09/00:03:24
(*, 224.0.1.40), 04:08:08/00:02:20, RP 172.16.100.1, flags: SJPCL
Incoming interface: GigabitEthernet1.24, RPF nbr 10.2.4.2
Outgoing interface list: Null
R4#sh derived-config interface tun0
interface Tunnel0
ip unnumbered Loopback0
no ip redirects
ip mtu 1500
tunnel source Loopback0
tunnel mode gre multipoint
R4#sh derived-config interface tun0
interface Tunnel0
ip unnumbered Loopback0
no ip redirects
ip mtu 1500
tunnel source Loopback0
tunnel mode gre multipoint
R4#sh ip pim vrf MCAST neighbor | b ^Neighbor
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.4.8.8 GigabitEthernet1.48 14:02:08/00:01:23 v2 0 / S P G
172.16.100.3 Tunnel0 12:04:08/00:01:36 v2 1 / S P G
10.4.7.7 GigabitEthernet1.47 11:50:02/00:01:26 v2 0 / S P G
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
10.4.8.8 GigabitEthernet1.48 14:02:08/00:01:23 v2 0 / S P G
172.16.100.3 Tunnel0 12:04:08/00:01:36 v2 1 / S P G
10.4.7.7 GigabitEthernet1.47 11:50:02/00:01:26 v2 0 / S P G
---------------------Test reachability---------------------
R5#ping 224.1.1.1 repeat 2
Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 224.1.1.1, timeout is 2 seconds:
Reply to request 0 from 10.4.8.8, 43 ms
Reply to request 0 from 10.4.8.8, 51 ms
Reply to request 0 from 10.4.7.7, 46 ms
Reply to request 0 from 10.4.7.7, 43 ms
Reply to request 1 from 10.4.7.7, 13 ms
Reply to request 1 from 10.4.8.8, 13 ms
Reply to request 1 from 10.4.8.8, 13 ms
Reply to request 1 from 10.4.7.7, 13 ms
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