It's a worthwhile point. While I think it's always better to design for "N" and not "2" I don't think I have ever seen more that two vNICs on a VM. For the primary reason that it's usually 1:1 app to VM (if you can run multiple apps in the OS, then just keep running Linux, move on and forge this whole virtualization fad)
The only argument I can think of for running more than 2 is bandwidth, but vNICs are not NICs and can be bound to any speed interface the hypervisor is willing to support. So bandwidth is not a reason to bond 7 vNICs to a VM. So while designing for N is logical, worrying too much about more than 2 vNICs per VM isn't terrible realistic. And as you said many many customers just run one vNIC per VM. J On Apr 17, 2013, at 4:15 PM, Truman Boyes <[email protected]> wrote: > Hilarious. > > Btw, is this multiple vNIC scenario based on real world experience? I am > scared of more than 1 vNIC in a large scale deployment due to complexities in > routing at the host level and further upstream. > > There may be corner cases the require a different set of reachable vectors > for a vm but there are many ways to provide that without more vNICs. Not > completely opposed to the idea, but when I see scenarios discussing VMs with > 5 vNICs I think the IETF may be off course here. > > There is a lot of rope, it's our choice to make a raft or a noose. > > > Truman > > > On Wednesday, April 17, 2013, John E Drake wrote: >> This thread reminds me of the lyrics to a Nicki Minaj song. >> >> >> >> Irrespectively Yours, >> >> >> >> John >> >> >> >> From: [email protected] [mailto:[email protected]] On Behalf Of Qin >> Wu >> Sent: Tuesday, April 16, 2013 7:15 PM >> To: Larry Kreeger (kreeger); Anoop Ghanwani; Black, David >> Cc: [email protected]; Reith, Lothar >> Subject: [nvo3] 答复: 答复: 答复: 答复: NVO3 Terminology changes >> >> >> >> Hi, Larry: >> >> Is relation between vNIC and TSI one to one or one to more? >> >> Let me interpret what you said below, >> >> (a)If a VM has only one vNIC, then vNIC that belongs to the VM will be dealt >> with as one tenant system. Each vNIC corresponds to one TSI. >> >> (b) If a VM has 5 vNICs and each vNIC is assigned with only one IP address, >> each vNIC that belongs to the same VM will be treated as one Tenant System. >> Each vNIC corresponds to one TSI. Then one VM have 5 Tenant system. Each >> Tenant System has one TSI. >> >> (c) If a VM has 5 vNICs and each vNIC is assigned with 2 IP addresses, each >> vNIC that belongs to the same VM will be treated as one Tenant system, each >> vNIC with each IP address corresponds to one TSI. Then one VM has 5 tenant >> system. Each Tenant system has 2 TSIs. >> >> That is to say if the relation between vNIC and TSi is one to more, then we >> can easy to guarantee that each TSI is associated with only one NVE. >> >> >> >> However if one VM is simply regarded as one tenant system and each vNIC with >> multiple IP addresses belonging to one VM is treated as only one TSI in >> (b)(c), take (c) as an example. when one vNIC is assigned with multiple IP >> addresses and connect to multiple VNs through multiple NVE, then one TSI has >> multiple IP addresses and will be associated with multiple NVEs. >> >> Here is two figure2, figure 1 shows one to one relation between vNIC and >> TSI, figure 2 shows one to more relation between vNIC and TSI. >> > _______________________________________________ > nvo3 mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/nvo3
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