Cisco Bug: CSCvv09810 - S,G not found in reciever VRF hence no Extranet in source VRF
Sep 02, 2020
- Cisco Nexus 9000 Series Switches
Known Affected Releases
Symptom: For a local receiver that is added by IGMP, there is no extranet linkage for the S,G in the source VRF table. The source VRF table's S,G outgoing interface (OIF) will not contain the extranet OIF list. Conditions: In this case, the extranet receiver is directly attached and the *,G is added by IGMP to MRIB. MRIB does an RPF lookup and due to the extranet configuration, creates a route in the source VRF table and attaches the receiver VRF table route to the source VRF table route. When the S,G gets created in the source VRF table, it is first created in PIM due to the receipt of the PIM register and creates an S,G in MRIB. Since there was an extranet linkage on the *,G in PIM, PIM does an inherit extranet route from the source VRF table to the receiver VRF table and creates the S,G in receiver VRF table, which attaches to the source S,G. However, when the *,G gets expired in IGMP due a leave, the attachment(link) is detatched only in MRIB, but not in PIM. MRIB just sends a prune notification and attached removal notification to PIM, but extranet links are not removed because of this in PIM. Routes are left to expire in PIM. If in this window, a new Join comes to IGMP and adds to MRIB, there is no inheritance to S,G in MRIB, since (as mentioned above) S,G attachment ALWAYS has to come from PIM or route creation in PIM.
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