Configuring Multicast on Cisco Router

[devang patel]

Hi All,

This time I am posting configuration for IP Multicast on your Cisco router. If any one need further help feel free to contact me.

 

Multicast:

As a simple defination of multicast is ONE to MANY or MANY to MANY communication (remember To ALL will become broadcast)

Multicasting is becoming a part of critical business technology. Streaming of Video, Presentation as well as audio contents with in Local Corporate network or on Internet is becoming very common. Application like IPTV is the out put of Multicasting technology. Here I am going to write down some commands you can use on your Cisco Router to configure IP Multicast.

1. IP Multicast Support Global
First of all look at the topology or network diagram and figure out how your multicast data will flow down which particular path. Identify the network devices (Routers/Switches) in a path and enable IP Multicasting support at very first. (This is same as to enable the IPv6 support, MPLS support as well as CEF on devices, of course each and every technology use different command to enable on it)

#ip multicast-routing

2. IP Multicast support on interface
Now enable the IP Multicast mode support on interface level of the same device which you identified in first step.

config-if)# ip pim sparse-mode (or you can enable Dense-mode/sparse-dense-mode as per your requirement).

Sparse-mode where you can have RP in network, each source and receiver will register or send join message to RP in order to deliver or receive the multicast data, In sort RP will be the root from where all multicast data will be distributed as well as collected.

Dense-mode where you can receive data directly from the source, receiver will join source directly, there is no any RP concept, Dense-mode uses the flood and prune process (3 min).
here source will be the root.

Sparse-Desnse-mode, where your network is supporting both the mode. Auto-RP need this both the mode in network to support RP announce and RP discovery process (as this process is Dense-mode dependent). Here you can have optimization of your resources with the help of SPT switch over process. You can avoid switchover from RPT to SPT using command
config)# ip pim spt-threshold infinity (depends on your requirement)

3. Static RP configuration

config)# ip pim rp-address 3.3.3.3 (auto-RP will get preference over the static RP)
or
config)# ip pim rp-address 3.3.3.3 override (to avoid the auto-RP Preference)
or
config)# ip pim rp-address 3.3.3.3 1
config)#access-list 1 224.3.3.3 0.0.0.0
(RP for particular group, in our case 224.3.3.3)

4. Auto-RP configuration
Here you need RP as well as Mapping Agent in network, RP will announce it self as an RP for the particular Multicast group using 224.0.1.39 address to Mapping agent call RP-announce, Mapping agent keeps the record of group to RP mapping and advertise that mapping in to the network using 224.0.1.40 address called RP-discovery.
You can have multiple router announcing as a RP for the different or same multicast group and can have multiple mapping agent at the same time. If Multiple router announcing RP for the same multicast group, Mapping agent will elect the Router with the highest IP address as a RP for that multicast group.

remember to enable SPARSE-DESNSE-MODE on required interface before enabling Auto-RP.

to announce router as RP
config)# ip pim send-rp-announce loopback 0 scope 255 group-list 3
config)# access-list 3 permit 224.3.3.3 0.0.0.0

to configure router as Mapping agent:
config)#ip pim send-rp-discovery loopback 0 scope 255

same way BSR configuration:
to announce router as candidate RP
#ip pim rp-candidate loopback 0 group-list 3
#access-list 3 permit 224.3.3.3 0.0.0.0

to announce router as BSR:
#ip pim bsr-candidate loopback 0 13 (13 is the priority value of BSR router)
if multiple router are claim to be BSR router then election will take place and router with higher priority will become a BSR.

5. Anycast RP:
Anycast: find the same profile router,server,etc... but nearest one in terms of lower hop-count, metrics or cost.

1. configure the loopback.

config)# interface loopback 3
config-if)# ip address 1.1.1.1 255.255.255.255
config-if)# ip address 3.3.3.3 255.255.255.255 secondary (you are going to this address as anycast, means you will have this same address configured on other routers or servers too)
config-if)#ip pim sparse-dense-mode

or instead of using secondary IP address you can use the different loopback address too.

2. MSDP peer config

config)# ip msdp peer 13.13.13.13 connect-source loopback 3
config)# ip msdp originator-id loopback 3

6. Stub Multicast Routing
Stubmutlicast routing will configure stuf router as IGMP proxy agent so it will forward IGMP message from host to the upstream multicast router, instead of fully speaking PIM functionality

config-if)# ip igmp helper-address 11.11.11.11

7. Verification and Monitoring command

1. sh ip mroute
2. sh ip pim interface
3. sh ip pim neighbor
4. sh ip pim rp mapping
5. sh ip igmp interface

8. to generate the Multicast data
config)# rtr 3
config-rtr)# type udpecho dest-ipaddr 224.3.3.3 dest-port 12345 control disable
config-rtr)# frequency 5
config-rtr)# end

9. to simulate the host
config-if)# ip igmp join-group 224.3.3.3
config-if)# ip igmp static-group 224.3.3.3

any updates or changes are always welcome...

Devang Patel

www.ipnetsol.net

[kaushal patel]

Very Nice..
Excellent

Kaushal

--
Kaushal Patel

[devang patel]

Kaushal,

Thanks for complement...
This post covers the topic related to Enterprise Multicasting needs as well as Service Provider Multicasting needs... still Multicast MPLSVPN is not covered in it... if needed then I will add that one too...

All,
Any particular topic requirement for the posting or help will be always welcome... I will be more than happy to help you guys in that regards...

regards
Devang Patel
www.ipnetsol.net