Subject: [armd] pain points ...

From: Kireeti Kompella <[email-masked]>
Date: Tue, 15 Nov 2011 19:30:08 -0800

The discussion of current pain points is important; however, we didn't just arrive here (well, I did; but most of you have been doing this a while).  What that means is that the current pain points are (to some extent) the result of "solving" earlier pain points.  Stepping back might be useful.

Freely re-interpreting Pedro, the tussle is between Layer 2 and Layer 3.  Here's why running the entire DC as a single L2 domain is (perceived as being) good:
1. L2 is "easy" -- plug-n-play, easy to configure, easy to understand, simple protocols.
2. L2 has a simple technique of network isolation (i.e., VLAN).
3. L2 isolation domains can be expanded and contracted very easily (add a VLAN to a port; add a host to a VLAN).
4. VMotion (for those who care) only works in L2 (today).
5. (Legacy) apps are written to run on a LAN (i.e., they expect clients and servers to live on the same subnet; they use LAN-wide services, e.g., DHCP).
6. Storage attaches easily at L2 (well, FC, FCoE, NAS, etc.) [this is NOT intended to start a FCoE vs. iSCSI war!]

Add to this the desire for "fungibility" of DC resources -- as Pedro put it, the desire to place a VM anywhere, and subsequently move it anywhere else; same for storage, firewalls, LBs, etc.  All this drives to _really_ large L2 domains.  And there begin new pain points …

So, we need, at one level, to address the pain points of massive DCs today.  But at another level, we need to address the underlying pain points (real and perceived).  I realize fully that I'm stepping off the cliff of ARMD's charter, but we (IETF) should do what's right, not just what's in this or that WG's charter.  And I agree with Pedro that a large part of that is moving more fully to L3.

Kireeti.

---

From: "Susan Hares" <[email-masked]>
Date: Tue, 15 Nov 2011 23:29:45 -0500

Kireeti: 

Could you update your message to include newer protocols at layer 2 control
plane SPBV and SPBM protocols and/or TRILL?  These provide multipath at
Layer 2, and large controllable Layer 2.   

Just a note, we have been strongly encouraged by Ron to not go outside our
charter until we finish our work at this point. I will follow Ron's
instructions.   

Sue 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Kireeti Kompella
Sent: Tuesday, November 15, 2011 10:30 PM
To: [email-masked]
Subject: [armd] pain points ...

The discussion of current pain points is important; however, we didn't just
arrive here (well, I did; but most of you have been doing this a while).
What that means is that the current pain points are (to some extent) the
result of "solving" earlier pain points.  Stepping back might be useful.

Freely re-interpreting Pedro, the tussle is between Layer 2 and Layer 3.
Here's why running the entire DC as a single L2 domain is (perceived as
being) good:
1. L2 is "easy" -- plug-n-play, easy to configure, easy to understand,
simple protocols.
2. L2 has a simple technique of network isolation (i.e., VLAN).
3. L2 isolation domains can be expanded and contracted very easily (add a
VLAN to a port; add a host to a VLAN).
4. VMotion (for those who care) only works in L2 (today).
5. (Legacy) apps are written to run on a LAN (i.e., they expect clients and
servers to live on the same subnet; they use LAN-wide services, e.g., DHCP).
6. Storage attaches easily at L2 (well, FC, FCoE, NAS, etc.) [this is NOT
intended to start a FCoE vs. iSCSI war!]

Add to this the desire for "fungibility" of DC resources -- as Pedro put it,
the desire to place a VM anywhere, and subsequently move it anywhere else;
same for storage, firewalls, LBs, etc.  All this drives to _really_ large L2
domains.  And there begin new pain points .

So, we need, at one level, to address the pain points of massive DCs today.
But at another level, we need to address the underlying pain points (real
and perceived).  I realize fully that I'm stepping off the cliff of ARMD's
charter, but we (IETF) should do what's right, not just what's in this or
that WG's charter.  And I agree with Pedro that a large part of that is
moving more fully to L3.

Kireeti.

_______________________________________________
armd mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/armd

---

From: Ronald Bonica <[email-masked]>
Date: Wed, 16 Nov 2011 04:18:05 -0500

Folks,

As with any working group, I have instructed ARMD to stay within its charter.

However, during this IETF, I have seen several WGs and BoFs trying to identify the pain points within the data center. This work should probably be centralized in one place. Over the next few weeks, I will seek to determine where that work should be done.

                                                         Ron

> From: Susan Hares [mailto:[email-masked]]
> Sent: Tuesday, November 15, 2011 11:30 PM
> To: Kireeti Kompella; [email-masked]
> Cc: Ronald Bonica
> Subject: RE: [armd] pain points ...
> 
> Kireeti:
>

---

From: "Susan Hares" <[email-masked]>
Date: Wed, 16 Nov 2011 18:05:51 -0500

Ron:

Being slow of understanding, does this mean you are "ok" with me discussing
this issues on ARMD until you find another place?

Sue 

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of
Ronald Bonica
Sent: Wednesday, November 16, 2011 4:18 AM
To: Susan Hares; Kireeti Kompella; [email-masked]
Subject: Re: [armd] pain points ...

Folks,

As with any working group, I have instructed ARMD to stay within its
charter.

However, during this IETF, I have seen several WGs and BoFs trying to
identify the pain points within the data center. This work should probably
be centralized in one place. Over the next few weeks, I will seek to
determine where that work should be done.

                                                         Ron

---

From: Ronald Bonica <[email-masked]>
Date: Wed, 16 Nov 2011 20:51:40 -0500

Sue,

For the time being, please proceed with the discussion. In the next week or so, we will figure out where the discussion needs to be.

                                 Ron

> Sent: Wednesday, November 16, 2011 6:06 PM
> To: Ronald Bonica; Kireeti Kompella; [email-masked]
> > Just a note, we have been strongly encouraged by Ron to not go
> outside
> > our
> > The discussion of current pain points is important; however, we
> didn't
> > just
> > 3. L2 isolation domains can be expanded and contracted very easily
> (add
> > a
> > 5. (Legacy) apps are written to run on a LAN (i.e., they expect
> clients
> > and
> > charter, but we (IETF) should do what's right, not just what's in
> this
> > or