Mailing List Archive

I was thinking... as far as my limited knowledge allows..

It seems that PPP or HDLC over OC-3 would be faster than
ATM over the same OC-3 circuit, and (at this stage) have fewer
interoperability problems.

But you can configure PVC's with ATM, working with an ATM
cloud, similar to frame relay, no? And if this is the case, then
a large backbone-type provider may desire to set up an ATM cloud,
making it easy to add POP's (just add them to the cloud), and allow
for more layer 2 routing (just configure PVC's between every POP you
have, building a full web, and a traceroute would now travel 2 or 4
hops instead of 12...?)

instead of some sort of hierarchichal star topology, you'd
have a large web...

and one more potential benefit to ATM -- won't it scale
very well to OC-12? ie, when you want to upgrade your network to
OC-12, you'd have no changes to make?

just thinkin... and I love it when y'all correct me, I tend
to learn a lot :)


On 20 May 1996, Camil Samaha/TEIR/Thomson wrote:

> I've been doing a lot reading the last few days on the advantages of "PPP over
> SONET/SDH" vs "IP over ATM AAL5". The available information bandwidth of
> roughly 150 Mbps out of 155.5 Mbps with STS-3c/STM-1 makes the PPP over SONET
> solution very attractive.
[...]

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> I've been doing a lot reading the last few days on the advantages of "PPP over
> SONET/SDH" vs "IP over ATM AAL5". The available information bandwidth of
> roughly 150 Mbps out of 155.5 Mbps with STS-3c/STM-1 makes the PPP over SONET
> solution very attractive.

Speaking SDH, it's VC4, so payload is 139.264Mbit (STS-3c SPE)


> I understand that SONET facilities are widely
> deployed throughout the carriers' broadband infrastructures but when will it
> become practical to run packet data over these facilities? I am aware that
> Cisco is planning to provide an OC-3/STM-1 interface in the 3d quarter but what
> about other hardware vendors?

> When will carriers be ready to support this service?

It's possible today, it's a matter of tariff, any SDH/Sonet network is
capable of doing this.

> Are multiplexers available or planned for the near future?

You can't do subrates, the rest is standard tranmission gear avaliable
from a variety of vendors.

> Are there carrier-to-carrier issues that need to be worked out?

It depends if you are buying this as a circiut within a network or as
two half circiuts. If you are obtainging two half-circiuts the two
corresponding carriers have to work out the maintenence procedures.


--Peter


Ps: ATM, what's that?
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On Tue, 21 May 1996, Peter Lothberg wrote:

> Or do you have many small OC-3 routers?
^^^^^^^^^^^^^^^^^^
Now, that's a thought! ;-)

Michael Dillon Voice: +1-604-546-8022
Memra Software Inc. Fax: +1-604-546-3049
http://www.memra.com E-mail: michael@memra.com

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> But you can configure PVC's with ATM, working with an ATM
> cloud, similar to frame relay, no? And if this is the case, then
> a large backbone-type provider may desire to set up an ATM cloud,
> making it easy to add POP's (just add them to the cloud), and allow
> for more layer 2 routing (just configure PVC's between every POP you
> have, building a full web, and a traceroute would now travel 2 or 4
> hops instead of 12...?)

If the number of hops that shows up in a traceroute is a design parameter
when building a network. And that is concidered higher than the overall
performance, yes.. IP over IP tunnels would also solve the problem -:)

(or disable loop detection by taking out the TTL decrement -:)

> instead of some sort of hierarchichal star topology, you'd
> have a large web...

Your ATM network topology will still likely be looking like what your IP
network would have looked, right?

In order to make efficient use of your cloud, all routers has to
be neighbours to all other routers, so in practice there is a limit to
the number of routers you can have.

Many large IP-networks are still built as logical star networks.

Depending on the size of your IP network, a lot of traffic will be
in/outbound to other ISP's, and here you need a router for various
reasons.

> and one more potential benefit to ATM -- won't it scale
> very well to OC-12? ie, when you want to upgrade your network to
> OC-12, you'd have no changes to make?

Asuming everyone talks to everyone, but, what router do you connect
at the edge that speaks OC-12? Or do you have many small OC-3 routers?

--Peter
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> On Tue, 21 May 1996, Peter Lothberg wrote:
>
> > Or do you have many small OC-3 routers?
> ^^^^^^^^^^^^^^^^^^
> Now, that's a thought! ;-)
>
> Michael Dillon Voice: +1-604-546-8022
> Memra Software Inc. Fax: +1-604-546-3049
> http://www.memra.com E-mail: michael@memra.com
>
>


Exponential growth, yes, well where do you think circiuts like this
will be before the end of the year?

Hssi2/0 is up, line protocol is up
Hardware is cxBus HSSI
Description: PL00190596 ICM-PEN-2<-->ICM-UK-1
Internet address is 198.67.131.25/29
MTU 4470 bytes, BW 45045 Kbit, DLY 200 usec, rely 255/255, load 248/255
Encapsulation HDLC, loopback not set, keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 5d02h
Output queue 0/40, 24883016 drops; input queue 0/75, 175 drops, 109723 flushes
5 minute input rate 21531000 bits/sec, 15203 packets/sec
5 minute output rate 43820000 bits/sec, 13082 packets/sec


-Peter
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