Hi Kevin,
I don't want to start a religious debate over which one is better than the
other so I am just giving the highlights of each two
POS (packet over sonet)
supported by multiple vendors including cisco, juniper and unisphere/siemens
based on sdh/sonet virtual containers
point-to-point
can run over darkfiber as well as over sdh/sonet
DPT
supported by cisco only, yet offered to IETf for standardisation
baesd on sdh/sonet virtual containers, can also run over DWDM
ring based, incl self-healing/wrapping
fair use algorithm
destination stripping vs source-stripping on SDH
DPT acts as a multi-access broadcast medium
A key question is if you do have the ability to build a ring topology on
your physical layer, if you don't then DPT will be nog good. If you do have
then you do have
the option for POS and DPT. It then really depends on your application what
you can choose, if you want to scale up to really high-speeds and do have
sufficient money to spend DPT might be the way to go. A key advantage of DPT
is the effcient use of bandwidth compared to SDH and that all the switching
is done in ASICS your users will generally see only to hops over the ring,
ingoing router and outgoing router.
Also if you do have enough dark-fiber available to build a ring consider
Gigabit Ethernet, much cheaper than the previous solutions, standardised to
a great extend and will be scaled uo to 10 Gig within the next couple of
years. However, don't forhet to turn off auto-negotioating on the cisco
boxes ;-)
Hope, my thoughts are heplfull to you
regards
cor van rij
sr. data networks engineer
versatel telecom int.
> -----Original Message-----
> From: kevin Young [SMTP:kvyoung@21cn.com]
> Sent: dinsdag 19 december 2000 16:07
> To: cisco-nsp@puck.nether.net
> Subject: [nsp] DPT vs POS
>
> hi,everyone
> there is a question puzzled me, i'm designing a metropolitan IP backbone
> network, there are two techs to fit it, DPT and POS, anyone give me some
> advices, thanks.
>
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