Subject: Re: [P2Prg] RE: DNS and P2P

From: "Ayyasamy, Senthilkumar \(UMKC-Student\)" <[email-masked]>
Date: Thu, 21 Aug 2003 05:44:22 -0500

>What doesn't map well is DNS' iterative search, the source of the pain that 
>you mention. At some point in DNS' implied overlay, a resolver has to 
>iteratively query zone servers. In the DHT systems, iteration is avoided by 
>transparent forwarding.

 The one you mention, iterative search and the associated resolution
delay is a *performance* pain.  huitema et all study and caida's strip 
charts illustrate that point. But, I was talking about *architectural* 
overload on the DNS system - which can be avoided using a P2P model. 
But, yes!!! It is way too ambitious...

>No debate here: naming is important. DNS and the canonical P2P applications 
>are the few applications where a name is known a priori and can be 
>"semantically meaningless". However, semantically meaningless names lose 
>prefix information (e.g., higher level DNS zone information). This can have 
>a negative impact on routing and forwarding in a P2P system.

  http://nms.lcs.mit.edu/projects/sfr/

>> Not extending DNS.. A better reference resolution model 
>> to reduce the overloading pain in DNS using proposed 
>> distributed object location routing systems.
>
>DNS is useful for bootstrapping. In P2P overlay construction, it allows us 
>to get a list of initial candidates and iteratively or recursively building 
>the overlay.
[...]

> But I wouldn't jump to the contusion that a brand new P2P-based 
> infrastructure for doing host name resolution just to add new 
> features is necessary or desireable. 

agreed. But, their is more... Recently, we invest a lot in overlay networks.
Since, backbone providers have no incentive to deploy stuff, researchers has
started to consider Internet as a "black-box" and design informed overlay
architectures at the application-level. After few years, we will have too
many overlays - either host based (end point multicast etc) or 
infrastructured (chord etc..) So, each of them will create a new name space 
+ indirection and depend on DNS for resolution/interaction between overlays.
This is really a major burden on DNS, not to mention the fact that we have 
done enough already (RFC 3467). Hence, it is very necessary to think about 
new approaches to solve this problem.

probably, we should move from DNS *lookup" to "search and update with
crawlers". A half-baked solution might be google can store all bindings 
and all local resolution can be re-directed to google for lookup. 

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From: "Raymond Gao" <[email-masked]>
Date: Thu, 21 Aug 2003 09:39:23 -0500

I just want to give my 2 cents worth here. Because DNS is an established
standard, it will be rather difficult to completely overturn it. Rewriting
it could cause complete rebuilt of Internet infrastructure. Rather, a
complimentary model between P2P and existing DNS standard has best chance of
succeeding. DNS is hierarchial vs. P2P is ad-hoc. In fact, routers (PGP/BGP
protocol) in DNS are pretty reliable. If we can add dynamic discovery
capability to it, somewhat like DHCP, it will be pretty nice. Here, I mean,
using PKI (key or token exchange) as the basis for assigning new ID and
address by rendezvous server to a new peer who is joining the horde.

Furthermore, it's inefficient for a simple peer to build a complete table of
the network and listing of all peers. That should reside on the more power
rendezvous or pack-manager/coordinator servers. A peer should have as much
information it needs. Building an extensive listing for the whole network
may have high-overhead, particularly if the network has hundreds, thousands,
or maybe millions of peers. Similarly, DHT is a good idea, although syncing
it across many servers will be a time & resource intensive task with
dependence on the underlying network.

-ray

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]On Behalf Of
> Ayyasamy, Senthilkumar (UMKC-Student)
> Sent: Thursday, August 21, 2003 5:44 AM
> To: [email-masked]
> Subject: Re: [P2Prg] RE: DNS and P2P
>
>

---

From: Scott Michel <[email-masked]>
Date: Thu, 21 Aug 2003 10:42:06 -0700

On Thu, Aug 21, 2003 at 05:44:22AM -0500, Ayyasamy, Senthilkumar  (UMKC-Student) wrote:
> delay is a *performance* pain.

It's not "a" but "THE" performance pain.

Also, "overloading" is ambiguous; is it functional or traffic overloading?
Functional overloading is quite true, there's a lot being stuffed into DNS
because it works well as a simple database query system that's very easy
to configure (and configure incorrectly.) Traffic overloading is a harder
case to make.

> new approaches to solve this problem.

I took your original point to mean "replace DNS", but here, you're arguing
that DNS needs augmenting, which I happen to agree with. Nonetheless, with
whatever overlays or overlay+infrastructures get used, there's still the
need to treat the peer network topology construction as an individual function.
Part of what you're proposing is using an overlay to bootstrap overlays
and the need for interoperation between overlays.

I'm not entirely convinced that semantically meaningless names solve much more
than sociopolitical problems, as the SFR page points out. If another layer of
name indirection is needed, there needs to be additional benefit. For example,
where do the mappings between a reference and an object get established for
random objects? Is there always a one-to-one mapping between an object and
its reference? What happens if the object changes, does the reference stay
the same or change? How do references move or become aliases for an original
reference?

> and all local resolution can be re-directed to google for lookup. 

What happens when there is one name-to-many reference resolution? Consider
GRID workflow setup in which more than one available resource can satisfy
a stage in the workflow.

-scooter
to the same semantically free reference.

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From: "C. Wegrzyn" <[email-masked]>
Date: Thu, 21 Aug 2003 20:34:44 -0400

I'm not sure I agree with all of this. DNS is not a mechanism for 
finding things other than addresses using symbolic names. This is 
clearly the case even with things like ENUM.

Searching is better left to other devices. While Google comes to mind it 
isn't the best mechanism for searching for communities of people or skills.

Chuck Wegrzyn

---

From: Bill Yeager <[email-masked]>
Date: Thu, 21 Aug 2003 22:43:09 -0700

I think that whatever is done with P2P in this way it needs to be 
capable of handling the ad-hoc publication/removal and lookup of 
information describing billions of peer nodes in the worst case 
scenario. What should this information be? What is necessary and 
sufficient as a description to permit p2p communication? Should we use 
an overlay that is independent of the underlying infrastructure, and 
thus can be inherently mobile, and permit NATS to be transparent to the 
application? Etc .... Should the overlay be hierarchical much like 
IP.V6 routing, and thus permit the localization of publication to 
appropriate levels in the hierarchy, and allow lookup to gracefully 
climb the hierarchy?

It could be that extensions of DNS are possible to handle these 
scenarios. I'm not sure.

On Thursday, August 21, 2003, at 05:34 PM, C. Wegrzyn wrote:

> Searching is better left to other devices. While Google comes to mind 
> it isn't the best mechanism for searching for communities of people or 
> skills.
>
> Chuck Wegrzyn
>
>
> Scott Michel wrote:

---

From: Bill Yeager <[email-masked]>
Date: Fri, 22 Aug 2003 21:01:32 -0700

THis is a good point. If you look closely at DNS statistics, you will 
see it is THE bottle neck out there. We can gather URLs where this info 
is kept. I do like DHT and distributed content myself. See the work 
that is being done on Jxta by JPL to create a fully distributed P2P 
digital library with lots of redundancy.

ANother interesting project here (not on jxta but p2p) is LOCKSS by 
Dave Rosenthal. Here a reputation based trust system and voting is used 
to decide on what archived data is valid. Several large libraries are 
participating in this project to create redundant digital library 
archives. Right, a little off of the track ... It does not use DHT's 
but provides a mechanism to know which sources of indexed lookup info 
are to be believed.

On Thursday, August 21, 2003, at 03:44 AM, Ayyasamy, Senthilkumar 
(UMKC-Student) wrote:

> But, I was talking about *architectural*