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DCI Verification

For the DCI verification, the Inter-VLAN, Intra-VLAN and Inter-VRF flows are discussed here, so we can understand the path taken for the scenarios. For more information on VLAN Grouping used for test setup refer to Table 1.

Type 2 – Type 5 Seamless Stitching: Intra-VLAN Route Verification

(3-stage single leaf1--> 5-stage compute leaf1)

Below is a flow walkthrough for the Intra-VLAN. The route chosen is Type2. As an example, the VLAN and the host IPs from DC1 and DC4 are provided here.

  1. MAC-IP route for 10.10.0.85 is present in ethernet-switching table for the evpn-1 mac-vrf instance, in DC1.
  2. The bgp.evpn route table Type2 route received from each 3stage border leaf switches (below shows loopback IP of both border leaf switches, VNI11400.
  3. On 3-stage Borderleaf 1, the translation vni is configured for 11400.
  4. Border leaf switch learns about host IP 10.10.0.85 from the 5-stage border leaf switch via the DCI overlay (note the translation VNI 41400).

Type 2 – Type 5 Seamless Stitching: Inter-VLAN Flow Walkthrough

(3-stage leaf1 --> 5-stage compute leaf1)

Below is a flow walkthrough for the Inter-VLAN. The route chosen is Type 5. As an example, the VLAN and the host IPs from DC1 and DC4. Note that the VLANs are different.

  1. MAC-IP route is NOT present on 3stage leaf1 because vlan 1200 is not present on the leaf in DC1
  2. Type 5 route is present in RED VRF, learned via 3-stage DC1 border leaf switches. Loopback 192.168.255.2 and 192.168.255.3 are loopback IPs of DC1 border leaf switches.
  3. BGP evpn route in detail shows Type 5 route, VNI 20001.
  4. As seen in previous steps, Type 5 VNI is 20001. Configuration snippets show Red VRF Type 5 VNI.
  5. Notice that the 3-stage border leaf switch1 (DC1) receives both Type 2 and Type 5 route for host via the DCI BGP overlay. The Type 2 route would be rejected by 3-stage Leaf1 because vlan 1200 is not present.
  6. Border leaf switch1 uses the Type 5 route from red VRF to route traffic towards DC4.

Type 2 – Type 5 Seamless Stitching: Inter-VRF Flow Walkthrough

(3-stage leaf1 --> 5-stage compute leaf1)

Below is a flow walkthrough for the Inter-VRF. The route chosen by the Border leaf switch is the default route to the MX304 router external gateway where inter-vrf routing is performed and then after sending the packet back to the border leaf switch Type 5 route is chosen to remote border leaf switch. As an example walk through, the VLAN and the host IPs from DC1 and DC4. Note that the VRFs are different.

  1. The 3-stage leaf switch receives the packet in a RED VLAN. Even though the route is present in the BLUE VRF, the leaf is only able to do a route lookup from the RED VRF, which only points to a DEFAULT ROUTE to the border leaf.
  2. 3-stage single leaf switch, uses default route to 3-stage borderleaf 1, via Type 5 VRF VNI 20001.
  3. 3-stage border leaf switch1 receives packet on red VNI 20001 and does the same route lookup, resolving again to a default route. This default route points to external MX.
  4. MX304 router receives packet from RED logical interface on Borderleaf, and forwards back to DC1 border leaf switch1 on BLUE logical interface.
  5. DC1 border leaf switch1 can now do a route lookup in blue VRF, resolving to Type 5 VNI for BLUE across DCI.
  6. DC4 border leaf switch receives the packet and forwards to DC4 compute pod leaf switch1 on L3 VNI 20002.
  7. Compute pod leaf switch1 receives packet on L3 VNI. The nexthop for the L3 route is IRB interface, which is present in MAC-VRF instance.

Type 2 Seamless Stitching: Intra-VLAN

The flow is similar to Type 2 – Type 5 Seamless Stitching: Intra-VLAN Route verification. An example is provided here, the same VLAN and VRF with destination is used here.

The server leaf switch finds the Type 2 route in the mac-vrf evpn-1.evpn.0 route table. Hence the route chosen in this case is Type 2 route.

Type 2 Seamless Stitching: Inter-VRF

For Inter-VRF route the chosen path is the default route to the MX gateway from border leaf switch for inter-VRF routing. It uses Type 2 routes from border leaf switch to the remote data center collapsed leaf switch. In this case the path terminates at the collapsed leaf switch since it hosts the Host server. Below is the example.

  1. 3-stage leaf switch receives the packet in a RED VLAN. Even though the route is present in the BLUE VRF, the leaf is only able to do a route lookup from the RED VRF. This only points to a DEFAULT ROUTE to the border leaf.
  2. MX receives packet from RED logical interface (IFL) on Borderleaf, and forwards back to DC1 border leaf switch1 on BLUE logical interface (IFL).
  3. Border leaf switch 1 (DC1) receives the packet back and performs a lookup of the route in the blue.inet.0 table where it finds the IRB route. Then it performs a second lookup for the irb route in the mac-ip-table for evpn1 instance.