cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
654
Views
0
Helpful
4
Replies

Multicast over GRE issue

darron
Level 1
Level 1

Good day!

I've been messing with this configuration for about a week now and cannot figure out where the issue lies.

Site A configured for a GRE tunnel to Site B at a remote location and working great. The issue is that I don't seem to be passing multicast traffic across the tunnel to the remote location.

97.97.97.97 = Gigabit Interface (Site A Public IP- Static)

98.98.98.98 = Gigabit Interface (Site B Public IP- Dynamic)

10.1.1.1 = RP (Site A Loopback0)

10.5.5.1 = Multicast Source

10.5.5.239 = DHCP for Client devices

Site A

interface Tunnel0
description mGRE Tunnel
ip address 172.16.100.1 255.255.255.0
no ip redirects
ip pim sparse-mode
ip nhrp map multicast dynamic
ip nhrp network-id 1234
tunnel source 97.97.97.97
tunnel mode gre multipoint

ip route 10.100.0.0 255.255.255.0 172.16.100.2

Site B

interface Tunnel0
description mGRE Tunnel
ip address 172.16.100.2 255.255.255.0
no ip redirects
ip pim sparse-mode
ip nhrp map multicast dynamic
ip nhrp map 172.16.100.1 97.97.97.97
ip nhrp map multicast 10.1.1.1
ip nhrp network-id 1234
ip nhrp nhs 172.16.100.1
tunnel source GigabitEthernet0/0
tunnel mode gre multipoint

interface Vlan100
ip address 10.100.0.1 255.255.255.0
ip helper-address 10.5.5.239
ip pim sparse-mode

ip route 10.5.5.0 255.255.255.0 172.16.100.1

-----------------------------------------------------------------------------------------------------------------

SiteB#sh ip pim rp
Group: 239.255.255.250, RP: 10.1.1.1, uptime 00:15:29, expires never
Group: 239.255.53.10, RP: 10.1.1.1, uptime 00:15:19, expires never
Group: 224.0.1.40, RP: 10.1.1.1, uptime 1d00h, expires never

SiteB#sh ip pim ne
PIM Neighbor Table
Mode: B - Bidir Capable, DR - Designated Router, N - Default DR Priority,
P - Proxy Capable, S - State Refresh Capable, G - GenID Capable
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
172.16.100.1 Tunnel0 1d00h/00:01:16 v2 1 / S P G

SiteB#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group,
G - Received BGP C-Mroute, g - Sent BGP C-Mroute,
N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed,
Q - Received BGP S-A Route, q - Sent BGP S-A Route,
V - RD & Vector, v - Vector, p - PIM Joins on route,
x - VxLAN group
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 239.255.255.250), 00:17:06/00:02:46, RP 10.1.1.1, flags: SJC
Incoming interface: GigabitEthernet0/0, RPF nbr 10.1.1.1
Outgoing interface list:
Vlan100, Forward/Sparse, 00:17:06/00:02:46

(*, 239.255.53.10), 00:16:56/00:02:51, RP 10.1.1.1, flags: SJC
Incoming interface: GigabitEthernet0/0, RPF nbr 10.1.1.1
Outgoing interface list:
Vlan100, Forward/Sparse, 00:16:56/00:02:51

(*, 224.0.1.40), 1d00h/00:02:44, RP 10.1.1.1, flags: SJCL
Incoming interface: GigabitEthernet0/0, RPF nbr 10.1.1.1
Outgoing interface list:
Tunnel0, Forward/Sparse, 00:20:26/00:02:44

SiteB#ping 10.5.5.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.5.5.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 60/63/68 ms

SiteB#traceroute 10.5.5.1
Type escape sequence to abort.
Tracing the route to 10.5.5.1 
VRF info: (vrf in name/id, vrf out name/id)
1 172.16.100.1 64 msec 68 msec 68 msec
2 10.254.106.2 72 msec 72 msec 64 msec
3 10.5.5.1 60 msec 60 msec 68 msec

I'm looking for any assistance on this...

4 Replies 4

darron
Level 1
Level 1

Is there more information needed for troublshooting?

Hello.

From site B your RP is reachable via G0/0, but should be over PIM-enabled interface (tunnel).

PS: if it's mGRE - you will need nbma pim behaviour + NHS mush be DR, but if you keep only two devices - migrate to a simple GRE tunnel.

I suspect RFC failure cause the problem, can you please show ip mroute count on both sides?

What is the use of "count" if RPF interface is incorrect?

Review Cisco Networking for a $25 gift card