Subject: Re: [alto] ***SPAM*** 7.152 (5) questions about the information alto server has

From: Richard Alimi <[email-masked]>
Date: Mon, 12 Jul 2010 10:10:31 -0400

Hi Xiao,

2010/6/22 朱潇 <[email-masked]>:
> hi,all
> some problems have risen up when I read the alto protocol draft. i  am not
> sure whether we disuses the similar problem or not, `cause I has not yet
> tried to retriev the maillist to find the answers. So some help may badly
> needed!
> 1 does alto server only need the information about traffic to optimize the
> peer selection? if yes,does the relative information needs the Peers`
> contributions, or just operators` own bossiness? If Peers` help are needed,
> how does Peer to upload or tell the alto server the relative information,for
> i did not catch the point in the alto protocol draft, or i miss it ?

The ALTO Server may take into account any information available when
determining costs between endpoints (and aggregation into PIDs).

That said, the ALTO Protocol does not provide any mechanism for
acquiring this information, meaning that a mechanism for gathering
information from applications peers' directly is not provided.  This
is intentional since the idea was for the ALTO Server to be
application-independent.

In the P4P trial, we had a third system component called the
Application Optimization Engine.  The tracker gathered information
(upload/download capacity estimates) from peers, aggregated the
information, and sent it to the Application Optimization Engine.  The
Application Optimization Engine also downloaded the ALTO network map
and cost map.  It then combined both pieces of information to provide
peering guidance which was then returned to the Tracker and use when
performing peer selections.

> 2 i noticed that the alto server discovery has been discussed, and we
> proposed some solution to solve the problem, finally some solution were
> merged into alto server capability in alto protocol, does i understand
> right?if yes, how does the problem the alto server discovery be solved
> through the server capability, which i can not understand well.
> can anyone be very kind to give me some guidance,(just like alto server:) )
> thx a lot!

The ALTO discovery protocol is not merged into the protocol document.
The Server List message in the current draft is meant to aid an ALTO
Client in discovering a different ALTO Server with other capabilities
after one has already been found.

Rich

---

From: Richard Alimi <[email-masked]>
Date: Tue, 13 Jul 2010 20:18:54 -0400

Hi Xiao,

Please see inline:

2010/7/13 朱潇 <[email-masked]>:
> Hi, Richard
> thanks for your detailed explanation:) i am very appreciated.
> some discussions are attached by in-line comments. Your comments
> are welcomed.
>
> 在 2010年7月12日 下午9:30，Richard Alimi <[email-masked]>写道：
>>
>> Hi Xiao,
>>
>> so maybe the information from the PoP will be collected by ALTO server?

That is entirely possible. While the ALTO protocol does not provide
such a mechanism, it is entirely reasonable (and I would think likely)
for an ALTO Server to integrate with entities such as network
management systems.

>    will server list message be involved the ALTO server discovery? Because
> in my understanding, if the Server List message is meant to help to
> discovery a different ALTO Server with other capabilities after one has
> already been found, what is the criteria when doing the ALTO server
> discovery?

It is unclear (to me anyways) at this point since the discovery
mechanism is still being discussed.  Much of the focus on discovery up
until this point has been on finding the 'right' ALTO Server for the
particular network region of the client without regards to particular
capabilities provided by an ALTO Server.

> BTW: what does the delegation mean in the chapter 9.1
> Some ISPs have proposed the possibility of delegation, in which an ISP
> provides information for customer networks which do not wish to run ALTO
> Servers themselves. A consideration for delegation is that customer networks
> may wish to explicitly configure such delegation.

As a simple example, consider a campus network with a single upstream
provider.  The campus network may not wish to manage an ALTO Server
itself, so it could instead direct ALTO Clients within the campus
network to its upstream provider's ALTO Server.  There are a couple of
technical considerations here (purposefully not mentioning business
considerations). First, the upstream ISP's ALTO Server should be
configured properly such that ALTO Clients from the campus network
receive reasonable guidance.  Second, the campus network
administrators should be able to explicitly configure this delegation;
in the future, if the campus network wishes to run an ALTO Server, it
may un-configure the delegation and instead direct campus network ALTO
Clients to its own ALTO Server.  The progress that I have read thus
far on the discovery protocol seems that it would allow for this use
case.

Rich

>
>>
>> Rich
>
>
>
> --
> Best wishes,
>
> Beijing University of Posts & Telecommunications (BUPT)
> Zhu Xiao  ( 朱潇 )
> E-mail: [email-masked]
> mobile:+86 134-8881-9004
>

---

From: Richard Alimi <[email-masked]>
Date: Fri, 23 Jul 2010 22:26:46 -0400

Hi Xiao,

Please see inline:

2010/7/15 朱潇 <[email-masked]>:
> Hi Richard,
>
> thanks for your explanation:) see inline
> 在 2010年7月14日 上午8:18，Richard Alimi <[email-masked]>写道：
>>
>> Hi Xiao,
>>
>> Please see inline:
>>
>> >> > some problems have risen up when I read the alto protocol draft. i
>> >> >  am
>> >> > not
>> >> > 1 does alto server only need the information about traffic to
>> >> > optimize
>> >> > the
> what is your understanding about how does the ALTO server fulfill the
> endpoints property and endpoints cost services? All about the endpoints
> information related to traffic comes from PoP?

As they are defined, the endpoint property and endpoint cost services
are generic and could carry properties and costs that are derived from
multiple sources. See Figure 1 in draft-ietf-alto-protocol-05 for an
illustration.

For example, for the endpoint cost service, the source of the
information may depend on the type of cost.  If the cost is a
hop-count, then computation from a static network topology may be
enough.  As another possibility, an ALTO Server may also take into
account aggregated traffic statistics (as was done in the P4P SIGCOMM
2008 paper).  The decision made by the provider of the ALTO Service.

Does this answer the question?

Thanks,
Rich