+1 for David comments. Also if we can add some text w.r.t use cases of handling of L2/L3 service combination will be good.
Regards, Balaji.P > IMHO, it should be architecturally the same, and we should say so. The > quoted text was intended to head in that direction, so an explicit > statement > seems like a fine idea. I think the touchstone for how L3 service is > provided > in an L2/L3 service combination should be: "what would happen if there > was no network virtualization?" > -----Original Message----- > From: nvo3 [mailto:[email protected]] On Behalf Of Black, David > Sent: Saturday, November 23, 2013 6:10 AM > To: Erik Nordmark > Cc: [email protected] > Subject: Re: [nvo3] Fwd: Arch: proposed text for Combined L2/L3 Service > > Writing as an individual, not co-author of draft-narten-nvo3-arch: > > > What is missing for me is a higher-level statement whether or not we > > see an NVE providing combined L2 and L3 service as being > > architecturally different that the non-overlay case of a bridge+router > > that provides combined service L2 and L3 today. > > > > If we think it is just the same architecturally, then it would make > > sense to state that. If we think it is different, then I think we need > > more details that Thomas' text above. > > IMHO, it should be architecturally the same, and we should say so. The > quoted text was intended to head in that direction, so an explicit > statement > seems like a fine idea. I think the touchstone for how L3 service is > provided > in an L2/L3 service combination should be: "what would happen if there > was no network virtualization?" > > Thanks, > --David > > > -----Original Message----- > > From: nvo3 [mailto:[email protected]] On Behalf Of Erik Nordmark > > Sent: Friday, November 22, 2013 2:12 PM > > To: Pankaj Garg; Vivek Kumar; Larry Kreeger (kreeger); Lucy yong; > > Thomas Narten > > Cc: [email protected]; Linda Dunbar > > Subject: Re: [nvo3] Fwd: Arch: proposed text for Combined L2/L3 > > Service > > > > On 11/20/13 12:07 AM, Pankaj Garg wrote: > > > Wouldn't the decision to do L2 or L3 service be based on the inner > > > frame > > fields i.e. destination MAC/IP in the inner frame? Similar to how > > switches/routers process packets i.e. based on frame's destination MAC > > and destination IP address (if present)? > > > > > > IMHO, Thomas's original text (pasted below) describes this quite > > > well and > > concisely. > > > > > >>> <t> > > >>> A virtual network can also provide a combined L2 and L3 > > >>> service to tenants. In such cases, a tenant sends and > > >>> receives both L2 and L3 packets. An NVE recieving > packets > > >>> from a TS determines the type of service to be applied > to > > >>> the packet on a per-packet basis as indicated by the > > >>> packet's destination MAC address as provided by the TS. > If > > >>> the MAC address corresponds to that of an L3 router (as > > >>> determined by the NVE), traffic is given L3 > > >>> semantics. Otherwise, the packet is given L2 service > > >>> semantics. A combined L2/L3 service presents no special > > >>> considerations for NVO3, other than packets received > from a > > >>> tenant must be classified as to what type of service > they > > >>> are to be given before they can be processed. > > >>> </t> > > > > What is missing for me is a higher-level statement whether or not we > > see an NVE providing combined L2 and L3 service as being > > architecturally different that the non-overlay case of a bridge+router > > that provides combined service L2 and L3 today. > > > > If we think it is just the same architecturally, then it would make > > sense to state that. If we think it is different, then I think we need > > more details that Thomas' text above. > > > > FWIW the existing bridge+routers handle multicast conceptually as > > bridge-route-bridge. A received multicast packet might need to be > > bridged out other L2 ports in the same bridge domain. Then one copy of > > packet is passed to the L3 function, which does L3 multicast routing > > (check iIF, decrement ttl, determine oIFs). Finally, a given L3 oIF > > might correspond to a bridge domain i.e., multiple packets might need > > to be sent out different L2 ports for each oIF. > > > > While that is a bit complex, it is a lot better if the NVO3 > > architecture is the same as existing combined bridge+router boxes. > > > > And note that an existing combined bridge+router is architecturally > > consistent with separate bridges and a router where the bridges only > > do > > L2 and the router only does L3. > > > > Erik > > > > > > _______________________________________________ > > nvo3 mailing list > > [email protected] > > https://www.ietf.org/mailman/listinfo/nvo3 > > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3 _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
