Linda,

See my replies below.

Marc

________________________________
From: Linda Dunbar [mailto:[email protected]]
Sent: Thursday, October 04, 2012 10:30 PM
To: [email protected]; LASSERRE, MARC (MARC); Balus, Florin Stelian (Florin); 
[email protected]; [email protected]; Yakov Rekhter
Subject: FW: [nvo3] Questions/comments to draft-lasserre-nvo3-framework-03.txt

Marc, et al,

Here are my comments to the "nv03-framework" sent a month ago. Could you please 
address them?

I want to echo Lucy's comment that behavior might be different when NVE  is 
directly connected to TES via virtual link or physical link (a.k.a. Trivial L2 
domain in Yakov's mobility draft) vs. there is switch( or switches) between NVE 
and TES.
Sure the behaviour is different but this does not call for another TES-NVE 
interface type besides a VAP. Several private emails have been exchanged with 
Lucy on this topic.

Linda

From: [email protected] [mailto:[email protected]] On Behalf Of Linda 
Dunbar
Sent: Tuesday, September 04, 2012 12:41 PM
To: Bocci, Matthew (Matthew); [email protected]; LASSERRE, MARC (MARC); Balus, 
Florin Stelian (Florin); [email protected]; [email protected]; 
Yakov Rekhter
Subject: [nvo3] Questions/comments to draft-lasserre-nvo3-framework-03.txt

Marc, et al,

I have a few questions on the draft, hope you can clarify:


1.      What does it mean by NVE being embedded in an End Station (as quoted 
from the document)?

NVE could be implemented as part of a virtual switch
within a hypervisor, a physical switch or router, a Network Service
Appliance or even be embedded within an End Station.

Do you mean a Guest OS which send IP frame directly? If yes, why need extra 
layer of IP encapsulation?

[ml] Since it should have read "... within an tenant system", this makes it 
redundant as tenant system can be any of the elements mentioned before in this 
sentence.
[ml] I will clarify this in -01.




2.      VN Context vs. VNID: do you mean that encapsulation header includes 
field for VN context in addition to VNID? Why need both fields?

[ml] You should read the text carefully. The draft says that in section 3.1.3 
that a VNID can be used as a VN context when globally significant.

3.      Definition to "Virtual Data Center or Virtual DC": when you say 
"Managed by a single tenant, Virtual DC can contain multiple VNs and multiple 
Tenant End System..", is the "single tenant" in the sentence one of the 
"multiple Tenant" in the sentence?

[ml] The sentence says: "Managed by a single tenant, a Virtual DC can contain 
multiple VNs and multiple Tenant End Systems  that are connected to one or more 
of these VNs."

[ml] Hence, a tenant manages multiples tenant end systems and not multiple 
tenants.

Could  it be more clear to remove the phrase "Managed by a single tenant"?


Other comments:

*        2.1 Generic Reference Model:



The Figure 3 depicts all the Tenant End Systems being directly connected to NV 
Edge, make the network looks like closed communication pattern.

When applications in DC communicate with peers somewhere else, the NVE function 
might be on gateway, which connects to remote peers via Internet or secure VPN. 
I suggest to have a dotted line behind one or two "NV Edge" to show that some 
Tenant End Systems are connected to NV Edge via another network (like Internet 
or secure IPSec or VPN).



[ml] Agreed, but this is generic reference model where all connectivity details 
can not represented.

When "VM-a" talk to remote peer "b" and  "b" is in another DC which doesn't 
have NVo3 encapsulation, Then the NVE for "b" is on the Gateway of DC where 
"VM-a" is hosted.  In this scenario the "b" doesn't connect to its NVE via 
Ethernet. So the statement on P11 "either directly or via a switched network 
(typically

Ethernet)" is not true all the time.

[ml] To make it clearer and more generic, how about saying "either directly or 
indirectly"?


*        3.1.5.1  Auto-provisioning/service discovery:



Your description states that "NVEs being able to select appropriate VNI based 
on state information provided by external entities".



Then it is not really "auto-provisioning". It should be classified as  "static 
provisioning".

[ml] That state can be provided in a non-static way - hence auto-provisioning.



"A mechanism for communicating this information between Tenant End Systems and 
the local NVE" can be one way, other approaches should be possible too.



It is necessary to consider the scenario that  "Tenant End Systems" doesn't 
have any capability to communicate with NVE. Then external controller has to 
communicate with the NVE for any new ES being added/removed.

[ml] Yes, and an external controller is such a mechanism. The original sentence 
includes this possibility.



*        3.2 Service Overlay Topologies:

I am confused of this intent of this section. Your second paragraph states that 
mesh connection between NVEs.

Since it is Layer 3 that interconnect NVEs, we should not assume that NVEs are 
only one hop away from each other.



[ml] The intent was not to assume that full mesh connectivity is required.



*        4.1 Pros & Cons:

Should add a point that Overlay push the burden to edge devices (i.e. NVEs). 
For NVEs on gateway routers in DC, managing the mapping between End stations 
and tunnels can be challenging.




Linda Dunbar

From: [email protected] [mailto:[email protected]] On Behalf Of Bocci, 
Matthew (Matthew)
Sent: Wednesday, August 29, 2012 11:01 AM
To: [email protected]
Subject: [nvo3] Poll for WG adoption: draft-lasserre-nvo3-framework-03.txt

This email begins a poll to help gauge consensus to adopt 
draft-lasserre-nvo3-framework-03.txt as an NVO3 working group document.

Since this is the second call for adoption, and only a few changes were 
requested during the last call for adoption, we will be running this call for 
10 days, only.

If you support adoption of draft-lasserre-nvo3-framework-03.txt, please reply 
to this thread with 'support'.

If you do not support adoption, please reply to this thread with 'do not 
support', and state your reasons.

This poll will close on Friday 7th September 2012.

Regards

Matthew & Benson

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