Hi Tony, There are two different cases in which a link is to be added to the FT temporarily. In one case, a negotiation is needed to be done before a link is to be added to the FT temporarily. In the other case, no negotiation is needed. It is determined that a link is added to the FT temporarily.
In section 5.1.5 or section 5.2.7, it seems that there is no details on negotiations. Best Regards, Huaimo From: Tony Li [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, May 14, 2019 4:31 PM To: Huaimo Chen <[email protected]> Cc: [email protected] Subject: Re: Flooding Negotiation bit Hi Huaimo, If I understand you correctly, this seems to have almost the same semantics as the Flooding Request TLV (section 5.1.5) or the Flooding Request Bit (section 5.2.7). If I’m not understanding you, could you please clarify the differences and why the current mechanisms are insufficient. Tony On May 14, 2019, at 1:09 PM, Huaimo Chen <[email protected]<mailto:[email protected]>> wrote: Hi Tony, For the case you described below, in order to add one or a limited number of links to the flooding topology temporarily, a new bit, called Flooding Negotiation bit (FN bit for short), should be defined and used. In OSPF, the FN bit is defined in Extended Options and Flag (EOF) TLV in OSPF Hello. In IS-IS, the FN bit is defined in the new TLV used for FR bit. When a node N (with 1000 interfaces/links for example) reboots, , each (node X) of the nodes connected to node N will establish an adjacency with node N. During the process of the adjacency establishment between node X and node N, node X sends a FN-bit set to one in its Hello to node N, node N selects one link/node (or a limited number of links) for temporarily flooding and sends only to this selected node a FN-bit set to one in its Hello. Node N adds the selected link/node to the FT temporarily after receiving the FT bit set to one from the selected node. After receiving the FN bit set to one from node N, the selected node adds the link (connected to node N) to the FT temporarily. In other words, a node Y connected to node N adds the link to node N to the FT temporarily after it sends and receives the FT bit set to one to/from node N; node N adds a selected link to the FT temporarily after it receives and sends the FT bit set to one from/to node Y. Best Regards, Huaimo ==== A case from Tony on 3/6 ==== If the node that rebooted has 1000 interfaces, which interfaces should be temporarily added? Adding all of them is likely to trigger a cascade failure. The TLV allows us to signal which ones should be enabled.
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