Subject: [edu-team] IDR Tutorial for IETF 70

From: Margaret Wasserman <[email-masked]>
Date: Thu, 27 Sep 2007 10:32:56 -0400

Hi Geoff,

Thanks for presenting the IDR Tutorial at IETF 69.  As always, you  
did an excellent job of preparing and presenting your session.

However, the EDU Team discussed your tutorial and the feedback we  
received, and we have some thoughts about how to update the tutorial  
so that it will be even more useful to the IETF community.

What you presented was an excellent BGP tutorial, but you didn't  
present much information that couldn't be gleaned from reading RFCs.   
We know that you have a lot of knowledge about how IDR routing  
actually works in the wild -- What is the DFZ and why is it  
interesting?  Who peers with whom at what levels? What types of BGP  
filters do they use in which directions?  What controls are in place  
to prevent random BGP routes from hitting the DFZ?  What types of  
things can (and do) go wrong with the current system?  etc...

So, we'd be interested in seeing more of an introduction to the  
Internet IDR routing system than just an intro to BGP...

Other members of the EDU Team may want to chime in here with their  
suggestions, as well.

Would you be willing to update the tutorial along these lines and  
give it again at IETF 70?

Margaret

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---

From: Radia Perlman <[email-masked]>
Date: Thu, 27 Sep 2007 09:25:29 -0700

Yes, I strongly agree with what Margaret said. In addition, it might be 
nice to cover the
concept of incompatible policies with BGP, and whether such things occur 
in the wild, and if
not, how they are avoided. And to repeat some of what she said in 
different words...what
kinds of issues are people trying to solve with policies (e.g., I want 
to connect to A so A's
customers can talk to my customers, and want to connect to B so B's 
customers can talk
directly to my customers, but I don't want to let A and B use me as a 
through path)? (and
actually, that is about the only example people give -- can you give 
others?)

Also, how is money done? In other words, is there incentive to be a 
through carrier from A to B
because you get paid more money? Or is everything a flat rate so you are 
motivated to do
as little work as possible? Are the charging policies flat rate (if they 
are) because the protocols
don't do sufficient accounting, or the accounting isn't trusted?

Radia

Margaret Wasserman wrote:
>
> Hi Geoff,
>
> Thanks for presenting the IDR Tutorial at IETF 69.  As always, you did 
> an excellent job of preparing and presenting your session.
>
> Would you be willing to update the tutorial along these lines and give 
> it again at IETF 70?
>
> Margaret
>
>
>
>

---

From: Margaret Wasserman <[email-masked]>
Date: Fri, 28 Sep 2007 08:35:08 -0400

Thanks, Geoff.

I realize that we're asking a lot, and we trust you to do the best  
you can.  Although this may be a difficult task, you are, IMO, the  
most likely person to be able to pull it off.

One way to think about our comments is that people who have already  
read a bunch about IETF routing protocols (because there are books  
and the RFCs out there) still don't really understand what the  
operations folks mean when they talk about issues in the routing  
system, because we don't really know that terminology.  I've had  
multiple smart folks sit through talks on the route table growth in  
the DFZ and then lean over to me and ask me if I know what the DFZ  
is, for example.  Many of us don't really know if you are talking  
about routes on a single router, the union of all DFZ routes, the  
average number of routes per router or what...  Most of us don't  
really understand how peering works.  And some people (including me)  
don't understand what it would mean to put a level of indirection  
(such as LISP or other tiered routing schemes) somewhere in the  
Internet (not at the enterprise or DFZ boundary), because we don't  
understand what interesting levels exist between an enterprise and  
the DFZ, if any.

Given the amount of activity in this area in the IETF, including  
plenary discussions, there seem to be a lot of people who would like  
to understand this area better.  If there are any good references on  
this subject, it would also be good to include a list of them in your  
slide deck...  but I fear that most of this stuff isn't really  
written down.

Margaret

On Sep 27, 2007, at 6:00 PM, Geoff Huston wrote:

> Hmmm - what you both appear to want out of a couple of hours causes  
> my brain to hurt. I suppose that from my perspectives such topics as:
>
> what is the DFZ and why is it interesting
> who peers with whom at what level
> what BGP filters are used
> what controls exist
> what can go wrong
> what are incompatible policies and where do they exist
> who can you discover incompatible policies
> how is money done
>
> are all topics that can either be treated quickly, superficially  
> and poorly or topics that take ages to get into and assume a  
> massive amount of familiarity with routing that you probably know  
> the answers already.
>
> Having said that you are making a Big Ask here, I must admit that  
> the room in Chicago surprised me - many of the folk there knew all  
> about BGP the protocol and were asking for what you are asking
>
> So let me think about this and see what I can come up with
>
>  Geoff
>
> Radia Perlman wrote:
>> Yes, I strongly agree with what Margaret said. In addition, it  
>> might be nice to cover the
>> concept of incompatible policies with BGP, and whether such things  
>> occur in the wild, and if
>> kinds of issues are people trying to solve with policies (e.g., I  
>> want to connect to A so A's
>> customers can talk to my customers, and want to connect to B so  
>> B's customers can talk
>> directly to my customers, but I don't want to let A and B use me  
>> as a through path)? (and
>> actually, that is about the only example people give -- can you  
>> give others?)
>> Also, how is money done? In other words, is there incentive to be  
>> a through carrier from A to B
>> because you get paid more money? Or is everything a flat rate so  
>> you are motivated to do
>> as little work as possible? Are the charging policies flat rate  
>> (if they are) because the protocols
>>> Thanks for presenting the IDR Tutorial at IETF 69.  As always,  
>>> you did an excellent job of preparing and presenting your session.
>>>
>>> received, and we have some thoughts about how to update the  
>>> tutorial so that it will be even more useful to the IETF community.
>>>
>>> present much information that couldn't be gleaned from reading  
>>> RFCs.  We know that you have a lot of knowledge about how IDR  
>>> routing actually works in the wild -- What is the DFZ and why is  
>>> it interesting?  Who peers with whom at what levels? What types  
>>> of BGP filters do they use in which directions?  What controls  
>>> are in place to prevent random BGP routes from hitting the DFZ?   
>>> What types of things can (and do) go wrong with the current  
>>> system?  etc...
>>>
>>> Other members of the EDU Team may want to chime in here with  
>>> their suggestions, as well.
>>>

---

From: Geoff Huston <[email-masked]>
Date: Fri, 28 Sep 2007 08:00:28 +1000

Hmmm - what you both appear to want out of a couple of hours causes my 
brain to hurt. I suppose that from my perspectives such topics as:

are all topics that can either be treated quickly, superficially and 
poorly or topics that take ages to get into and assume a massive amount 
of familiarity with routing that you probably know the answers already.

Having said that you are making a Big Ask here, I must admit that the 
room in Chicago surprised me - many of the folk there knew all about BGP 
the protocol and were asking for what you are asking

  Geoff

---

From: Brian E Carpenter <[email-masked]>
Date: Mon, 01 Oct 2007 10:17:36 +1300

I had the pleasure of teaching BGP4 in half an hour
to a class of 3rd year undergraduates last week.
It can't be done :-). But preparing for it made me
realise that the amount of operational and business
baggage wrapped up in the phrases "autonomous system"
and "policy-based routing" is enormous, and almost totally
undocumented. (And yes, I did look at Radia's book while
preparing. I also recommended it as further reading.)
So I think that if nothing else can be done in the space
of a tutorial, demystifying those phrases and how they
relate to the mythical DFZ would be highly valuable.

Regards
    Brian Carpenter
    University of Auckland

On 2007-09-29 00:35, Margaret Wasserman wrote:
> 
> Thanks, Geoff.
> 
> I realize that we're asking a lot, and we trust you to do the best you 
> can.  Although this may be a difficult task, you are, IMO, the most 
> likely person to be able to pull it off.
> 
> One way to think about our comments is that people who have already read 
> a bunch about IETF routing protocols (because there are books and the 
> RFCs out there) still don't really understand what the operations folks 
> mean when they talk about issues in the routing system, because we don't 
> really know that terminology.  I've had multiple smart folks sit through 
> talks on the route table growth in the DFZ and then lean over to me and 
> ask me if I know what the DFZ is, for example.  Many of us don't really 
> know if you are talking about routes on a single router, the union of 
> all DFZ routes, the average number of routes per router or what...  Most 
> of us don't really understand how peering works.  And some people 
> (including me) don't understand what it would mean to put a level of 
> indirection (such as LISP or other tiered routing schemes) somewhere in 
> the Internet (not at the enterprise or DFZ boundary), because we don't 
> understand what interesting levels exist between an enterprise and the 
> DFZ, if any.
> 
> Given the amount of activity in this area in the IETF, including plenary 
> discussions, there seem to be a lot of people who would like to 
> understand this area better.  If there are any good references on this 
> subject, it would also be good to include a list of them in your slide 
> deck...  but I fear that most of this stuff isn't really written down.
> 
> Margaret
> 
> 
>> poorly or topics that take ages to get into and assume a massive 
>> amount of familiarity with routing that you probably know the answers 
>> already.
>>
>> room in Chicago surprised me - many of the folk there knew all about 
>> BGP the protocol and were asking for what you are asking
>>
>>> Yes, I strongly agree with what Margaret said. In addition, it might 
>>> be nice to cover the
>>> because you get paid more money? Or is everything a flat rate so you 
>>> are motivated to do
>>> as little work as possible? Are the charging policies flat rate (if 
>>> they are) because the protocols
>>>> routing actually works in the wild -- What is the DFZ and why is it