Need Support with Multicast Configuration

[conor.maton]

Hi all,

Please see attached my topology of my LAN/WAN with multicast source and receivers detailed.

Essentially I just want some clarification as to if the attached topology will work. See below further details:

Multicast Source Site

• The multicast source will be connected to a Cisco 3850 Access Switch with a LAN base licence. IGMP snooping will be enabled for that VLAN (if required)
• The VLAN SVI for the multicast source (default gateway) will be configured on the Cisco 3850 Core Switch with IP Services licence
• The Cisco 3850 Core Switch will have multicast routing and PIM-SM enabled on the interfaces connected to the Routers.
• The Cisco 3850 Core Switch has a static route to the WAN with a next hop address of the virtual HSRP address in a separate subnet. The HSRP routers will have HSRP Aware PIM enabled so the RP is configured on both but mcast traffic is sent to the active HSRP router. PIM-SM  will be enabled on the routers

Multicast Receiver Sites

• The routers will have PIM-SM enabled, will be running HSRP and will have a static route to the LAN with the next hop address of an SVI on the Core Switch (HSRP in a separate subnet)
• The Cisco 3850 Core Switch is deployed with a IP Base licence and will have ICMP snooping enabled in the HSRP VLAN and multicast receiver VLAN
• The Cisco 350 Access Switch has a LAN base licence which connects to the Cisco 3850 Core Switch. The multicast receivers will be connected to a Cisco 3850 Access Switch with a LAN base licence. IGMP snooping will be enabled for that VLAN

I am a little bit conscious that whilst my source methodology should work, my receiver topology won’t as I am not sure if the Core Switch requires PIM-SM enabled which I do not believe is possible with an IP Base licence.

Can you provide me some guidance of my design and advise accordingly please.

Many thanks in advance for your help, you guys are great! :)

[chrihussey]

Your concern is valid in at the receiver sites with the 3850 cores running IP Base. The SVI interfaces would need PIM-SM which is not available. I've never had to configure it myself, but it appears IP Base only supports PIM stub routing which has several limitations. Some being you cannot implement it on SVIs and you have to implement EIGRP stub routing.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3850/software/release/3.2_0_se/multibook/configuration_guide/b_consolidated_config_guide_3850_chapter_0101001.html#ID127

You might be able to make it work but it may be easier to:

1- Trunk from the routers to the cores and have the L3 interfaces on the routers thus just making the cores L2 devices.

2- Upgrade the cores to the IP services

Hope this helps

[conor.maton]

Hi chrihussey, thanks for your reply.

I have approximately 10 VLANs in total, however oly one needs to support multicast. Therefore I am deciding to keep the design as is, expect for that one VLAN which I will trunk to the Routers.

I see no reason why this wouldn't work. The trunk link will consist of the HSRP VLAN and the other VLAN (PA) in a router on a stick configuration and these will have IGMP snooping enabled up to the L3 interfaces and the L3 interfaces configured with PIM-SM.

[chrihussey]

Sounds good. If you run into any issues during the implementation just reply to this post.

Regards