Implementing Multicast Routing between NSX Edges and DellEMC Networking


This is a continuation to my previous article on Implementing IPv4 Multicast Routing with DellEMC Networking. The previous article covered the multicast routing for VLAN Segments on vSphere DVS, in case you missed it you can find it here:

https://vxplanet.com/2019/08/29/implementing-multicast-routing-between-vsphere-dvs-and-dellemc-networking/

In this article, we will extend multicast routing to NSX-V Edges, so that a multicast receiver on the Overlay Segment can successfully subscribe to a multicast stream on the VLAN Segment on vSphere DVS. 

NSX-V version 6.4.2 and later supports Multicast Routing for the Overlay Segments. PIM Sparse mode is supported on the ESG and not on the DLR. There are few other limitations that we need to be aware of.

  • An ESG cannot be a PIM Rendezvous Point (RP) or Bootstrap Router (BR)
  • Only a Single Tier ESG is supported
  • Only one downlink on ESG is supported, ie a single DLR
  • The Edge version that I am using is 6.4.4 which supports only a single uplink interface.
  • ESG Active-active high availability using ECMP is not supported.
  • L2 bridging is not supported on a logical switch with multicast routing.
  • Hardware VTEP gateways (ToR gateways) are not supported on a logical switch with multicast routing.

These limitations puts a requirement to have a dedicated ESG cluster for multicast routing. 

We will use the same multicast source used in the previous article. The source is a VM (vStream_Server_01) on VLAN 11 Port Group on vSphere DVS. The multicast application is a VLC video stream on group 239.2.2.15 running in vStream_Server_01. We will cover two multicast receiver scenarios here :

  • A multicast receiver connected to the ESG (Single Tier)
  • A multicast receiver connected to the DLR (Two Tier)

Multicast Receiver on ESG (Single Tier)

[Click here for HQ Image]

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The Environment details are the same as the previous article with the below changes:

  • Removed the Port Groups for VLAN 12 & 13 in DVS and introduced Port Group VLAN 210 for the ESG Uplink. 
  • Disabled IGMP Snooping for VLAN 12 & 13 on the ToR Switches and enabled for VLAN 210
  • Disabled PIM Sparse mode for VLAN 12 & 13 on the Core Switch and enabled for VLAN 210
  • Connected ESG Uplink to port group VLAN 210 (Network 192.168.210.0/24)
  • An Overlay Logical Segment is connected as downlink to the ESG (Network 172.16.50.0/24)
  • A multicast Receiver is connected to this Overlay Segment. 

Multicast Routing Configuration on ESG

The NSX-V version I am using is 6.4.4 which supports only one uplink and downlink interfaces for multicast routing. 

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These are the interfaces on the ESG. vnic0 is a downlink to the DLR which we will use for the next scenario. vnic1 is the uplink interface. vnic2 connects to the logical segment for multicast receivers.

[Click here for HQ Image]

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OSPF is configured between ESG , DLR and the Core switch and the networks are advertised. For simplicity, I used a common Area 0, but the best practice is to have OSPF NSSA between ESG and DLR for which I have a separate article.

https://vxplanet.com/2019/04/24/a-study-on-nsx-v-with-ospf-area-types-why-is-nssa-better-for-tenants-part-1/

https://vxplanet.com/2019/04/27/nsx-v-and-ospf-area-types-walkthrough-see-why-nssa-is-better-for-tenants-part-2/

[Click here for HQ Image]

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The PIM Rendezvous Point (RP) is a loopback interface on the Core switch. We need to make sure that the RP is reachable from the ESG.

104.png

Now, let’s enable Multicast routing on the ESG using the Toggle button. We could either use a static entry for RP or it would dynamically receive it as we have enabled auto-RP on the Core switch. For simplicity, I have used a static entry.

Note that due to limitations, only 1 uplink and 1 downlink interface on the ESG can be enabled for PIM. 

[Click here for HQ Image]

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Let’s confirm the settings from the CLI.

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Multicast Configuration on the Core Switch

The configuration is same as in the previous article except that PIM is enabled on VLAN 210. 

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Also the Loopback interface (RP) is advertised in OSPF for reachability.

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IGMP Snooping Configuration on the ToR Switches

IGMP Snooping is enabled on VLAN 210 on both ToR Switches

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ToR should learn the router port for IGMP Querier for VLAN 210. It thus sees interfaces to both the Core and ESG as router ports.

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Similarly for ToR2

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Verifying the PIM Neighbors

Now that PIM Multicast routing is configured, both Core Switch and ESG should see each other as PIM neighbors on VLAN 210

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Configuring the Multicast Receiver

Now let’s connect the Multicast Receiver VM (vStream_Receiver_01) to the Logical Segment connected to ESG.

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As done previously, configure VLC as a multicast Stream receiver for the group 239.2.2.15.

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It should be able to successfully join the multicast group. 

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Verifying the PIM and IGMP Tables

We should see that the IGMP table is updated with the receiver’s entry.

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The PIM multicast routing Table on the ESG should show (S,G) entry for the group 239.2.2.15 with the incoming and outgoing interfaces properly updated.

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Similarly on the Core Switch, we should see VLAN 210 as Outgoing interface in the PIM multicast Routing Table.

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Multicast Receiver on DLR (Two Tier)

[Click here for HQ image]

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Unlike ESG, DLR doesn’t have support for PIM Sparse mode. Enable Multicast Routing using the Toggle button. Specify the Replication Multicast Range based on the groups that we need to subscribe for and this should be outside the range used under the Transport zone for BUM Replication.

The IGMP Parameters should be identical to that used on the ESG.

[Click here for HQ image]

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Next, enable Multicast support for the ESG interface connecting  to the DLR. 

Now attach a multicast receiver to the Logical Segment (172.16.10.0/24) connected to the DLR. It should be able to subscribe to the multicast stream 239.2.2.15 from VLAN 12.

Like before, the IGMP and PIM tables on the ESG should be updated accordingly.

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Note that the Outgoing Interface for the [S,G) entry is vNic_0 which is the interface to the DLR.

This concludes the last of the two part series on multicast routing. I hope the article was informative. Thanks for reading.

 

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