10-14-2020 12:52 AM
Hello,
I needed to enable Layer 2 flooding on one little subnet/vlan and I have enabled it on Virtual Network of Host Onboarding section same as https://community.cisco.com/t5/networking-documents/cisco-sd-access-layer2-flooding/ta-p/3943916. However, when I tested ping to broadcast from one switch to another, it was not working. What else can be possible cause which prevent flooding? I have multicast enabled on the same network. DNAC version is 1.3.3.3
10-14-2020 11:03 AM
Do you have multicast enabled in the underlay?
10-14-2020 11:43 PM
@JL421-Retired , No, I don`t. I didn`t see it in any documentation requirement. Do you have any guide for it? Which mode? What node should be RP and etc.
10-15-2020 02:12 PM - edited 10-15-2020 02:24 PM
https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html#L2_Flooding
Generally you would configure your RPs on your LAN Automation seed devices, or on the Core/Distribution layer of your design. I'll see if I can find the deeper guide to setting up multicast for the underlay.
I can't find anything more in-depth than this excerpt: Manually configure multicast on all underlay devices. This includes ip multicast-routing globally and ip pim sparse-mode on all routed uplinks.
Looking through my configs, it really is a fairly sparse config:
Loopback0 - ip pim sparse-mode, ip router isis
Transports - ip pim sparse-mode
ip multicast-routing
ip pim rp-address $ipofanycastrp
ip pim register-source Loopback0
ip pim ssm default
Then on your RPs you add:
ip msdp peer $ipofpeer connect-source loopback0
Loopback60000 - Anycast ip address, ip router isis
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: