Hi Huaimo, Ad 1 - Let me observe that constructing hierarchy is not always driven by number of nodes in a given level can safely support. One could indeed build a global flat link state network in single level/area if only looking at number of nodes. But in number of cases benefits from hierarchy could be seen in reduced flooding radius and enforced summarization. Hint: me why my routers in Sydney have to be aware about link flap in POP in Toronto ?
Ad 6 - Interesting .. I asked the same question to authors offline :) Thx, R. On Mon, Aug 19, 2019 at 4:27 PM Huaimo Chen <[email protected]> wrote: > Support and have the following comments: > > > > 1. It seems not necessary to have 8 levels of hierarchies. 3 or at > most 4 levels of hierarchies should be enough. IS-IS with 3 levels of > hierarchies may support a network with 1k*1k*1k nodes, which is about 10^9 > = 1 billion nodes. IS-IS with 4 levels of hierarchies may support a network > with 1k*1k*1k*1k nodes, which is about 10^12 = 1 trillion nodes. > 2. For PDU type, section 2.2 of the draft proposes to use 8 bits (all > three reserved bits plus the 5 bits for the existing PDU type). It seems > better to use 6 bits (one reserved bit plus the 5 bits for the existing PDU > type). Adding one reserved bit into the PDU Type allows people to define 32 > new PDU types, which is enough for the new PDU types needed for new > hierarchies. > 3. Section 3 “Additional PDUs” of the draft, defines 6 new PDU Types > for ’Level n LAN IS to IS hello PDU’ (Ln-LAN-HELLO-PDU), where n is 3, 4, > 5, 6, 7, and 8. In addition, the following new PDU Types should be defined > (considering at most 4 levels of hierarchies): > 1. 2 new PDU Types for ‘’Level n LSP”, where n is 3, and 4 > 2. 2 new PDU Types for ‘’Level n CSNP”, where n is 3, and 4 > 3. 2 new PDU Types for ‘’Level n PSNP”, where n is 3, and 4 > 4. On a broadcast interface, Level 1 LSPs are multicast through MAC > 0x0180.c200.0014 (which is called AllL1ISs), and Level 2 LSPs are multicast > through MAC 0x0180.c200.0015 (which is called AllL2ISs). It seems that > Level n LSPs should be multicast through AllLnISs, where n is 3, and 4 > (considering at most 4 levels of hierarchies), thus > 1. 2 new MAC should be assigned to AllLnISs, where n is 3, and 4. > 5. The existing DIS for a broadcast interface periodically multicast > through AllL1ISs and AllL2ISs a Complete SNP (CSNP). It seems that the DIS > should be extended to periodically multicast a CSNP through AllLnISs, where > n is 1, 2, 3, and 4 (considering at most 4 levels of hierarchies). > 6. When there may be 3 or more levels of hierarchies, is it allowed to > have 3 or more levels (consecutive) configured on an interface? It seems > that there is no description about this in the draft. > > > > Best Regards, > > Huaimo > > > > *From:* Lsr <[email protected]> *On Behalf Of *Acee Lindem (acee) > *Sent:* Monday, August 12, 2019 10:33 AM > *To:* [email protected] > *Subject:* [Lsr] LSR Working Group Adoption Call for "Hierarchical IS-IS" > - draft-li-lsr-isis-hierarchical-isis-01 > > > > This begins a two week LSR Working Group Adoption Poll for the > "Hierarchical IS-IS" - draft-li-lsr-isis-hierarchical-isis-01. The poll > will end at 12:00 AM UTC on August 27th, 2019. Please indicate your > support of objection on this list prior to the end of the adoption poll. > > > > Thanks, > > Acee > _______________________________________________ > Lsr mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/lsr >
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