Re: LAN<-->WAN<-->LAN ; L3 switches or Routers??
- From: "stephen" <stephen_hope@xxxxxxxxxxxx>
- Date: Wed, 26 Jul 2006 19:34:58 GMT
<qazmlp1209@xxxxxxxxxxxxxx> wrote in message
news:1153888504.936713.323920@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
WAN.So something to consider is what hardware you need to interface to the
As I am aware, the following are the possible WAN transport options:
This is a good point as while Cisco high-end switches like the 6500
have FLEXWAN card to support more than just Ethernet connectivity this
is not the case on their low end switches.
So you might need routers and switches depending on the WAN transport
options available.
i was trying to point out that just because this is possible on a 6500
doesnt mean it is a good idea.
Personally i would try to use "real" routers for low end stuff, and LAN
optimised kit like a 6509 for Ethernet WAN connections.
- Point to point private links
this could be almost anything - usually PDH or SDH links - E1, T1, E3,
STM-1. easiest used to be flexWAN with 7200 style port adaptors (basically a
VIP if you know the 75xx routers). SPA can do the same for some interfaces.
for "low speed" say up to 2 Mbps / 34 Mbps it may be cheaper and more
flexible to use a separate router.
- Gigabit Ethernetjust plug it into the Cat. Main issue is if you buy a rate limited port (ie.
20 Mbps of bandwidth presented on a 1 Gbps link). Normal LAN type ports on
the Cat cannot do traffic rate limiting in conjunction with QoS, but the
high end modules such OSM support this if you need it.
i understand cisco now recommend the SPA for this.
Same reasoning goes for the different speed ports 10G, 100M and 10M as long
as they are presented as Ethernet.
- ATMflexWAN adaptor or SPA.
pretty much obsolete for new links, but lots around and you might want it if
you already have
- Frame Relaysame as a serial (up to 34 Mbps, although not many high speed F/R links.
- SDH/SONET
OSM or SPA.
If you have lots of SDH, then you probably dont want a 6509.
However that much derided animal the SDH mux can give you very cheap wire
speed GigE thru SDH...... and if you have 10G SDH (STM-64 or SONET 192),
then a modern lambda transport will normally also support 10G Ethernet LAN
PHY - so use the Ethernet presentation instead.
What do you suggest for each of the above-mentioned WAN transport
options? Why?
Also, should the replacement cost also be considered while taking this
decision?
not sure what you mean here - there is an "oppotunity cost" - ie putting low
speed ports into a high speed chassis like a 6509 eats up slots but doesnt
give much thruput.
But - the cost of a slot in a 6509 is much less than in a more conventional
router - at work the "real" high end routers used to be7513s, and GSR12008.
Now new units are 10008s, GSR1241x, CRS-1.... (this is where the phrase
"carrier class" is used to justify 5 times the price for 1/3 or less ports,
although to be fair the boxes support much richer QoS, aggregated interfaces
and so on).
For some of the big iron routers a single card with a couple of ports costs
more than a 6509 full of LAN blades, so if the relatively reduced feature
set of the 6509 is "good enough", the cost per Gbps of the 6509 is much
better
--
Regards
stephen_hope@xxxxxxxxxxxx - replace xyz with ntl
.
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- From: qazmlp1209
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