Chuck,
Reflecting on my post, about the only thing that could be "proven" is that
they seem to call most of their newer/higher end models switch-routers......
I don't know if looking at the PPS is a great indication just because
technologies change and get better...... So I can't say that the higher PPS
of the 12000 and 8500 are due to multilayer switching only
I have alot of respect for you, so I don't want you to feel that I'm trying
to contradict you to make you look bad or anything.... I don't even think
it's possible for me to make you look bad =)
The whole point of all of this stuff was tho that Multilayer switching is a
great thing =)
Mike W.
"Michael L. Williams" wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> I think on any of those units, to reach it's maximum throughput you have
to
> enable and configure multilayer switching.....
>
> If you look at the name on the Cisco 12000 you'll see it's called a GSR =
> Gigabit Switch-Router. At this point, even Cisco realizes that it's
> incorrect to call it simply a router because anymore the combinations of
> switches and routers have been combined.
>
> The real funny thing is, out of all of the units you listed, Cisco only
> calls one of them a (plain) router, the 7600. The others are refered to
as
> either a switch-router or a multilayer switch. So, you'll notice the only
> router listed here can do 30 million PPS, while the two high end switches
> can do almost 6 times (170 mPPS) and then over 12 times (over an order of
> magnitude more) than the actual router....... so thank you for proving my
> point. =)
>
> Having said all that, my whole point is multilayer switching integrates
the
> best of routing and switching to provide better performance...... and I
> think my point has been proven.
>
> I wish I could log into CCO =(
>
> Mike W.
>
> "Chuck Larrieu" wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > So layer three switches are faster, 'eh? By orders of magnitude, 'eh?
This
> > calls for a bit of research on CCO.
> >
> > Hhhmmmmmmm................
> >
> > Catalyst 8500 = 24 million PPS
> > http://www.cisco.com/univercd/cc/td/doc/pcat/ca8500c.htm#CJAEJHDF
> >
> > Catalyst 6509 = 170 million PPS
> > http://www.cisco.com/univercd/cc/td/doc/pcat/ca6000.htm
> >
> > Cisco 12000 = 375 million PPS
> > http://www.cisco.com/univercd/cc/td/doc/pcat/12000.htm
> >
> > Cisco 7600 - 30 million PPS
> > http://www.cisco.com/univercd/cc/td/doc/pcat/7600.htm
> >
> >
> > so it would appear, based on Cisco's own product literature, that high
end
> > router versus high end switch, the edge most definitely goes to the
> product
> > Cisco calls a router. and numbers are all over the place, to judge from
> the
> > example I have looked at.
> >
> > Look, my point remains that any trickery, hardware or otherwise, can be
> > applied to "routers" as well as "switches".
> >
> > It most definitely is NOT enough to say that there is a difference and
it
> is
> > because of the hardware construction of a "switch" versus that of a
> "router"
> >
> > Chuck
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of
> > Michael L. Williams
> > Sent: Wednesday, June 06, 2001 8:52 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: Layer3 switch vs Router [7:7406]
> >
> > "Sergei Gearasimtchouk" wrote in message
> > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > > I am sorry, should have said some thing meaningful. :(
> > > hypothetically speaking, if the ACLs are in place, wire speed is gone.
> > > The concept route one switch many is no longer holds its value.
> >
> > That's what I thought you meant. I'm glad you clarified your position.
> >
> > But it's incorrect. Multilayer switching (& therefore wire speed
> "routing")
> > are out the door only when you have an ACL applied to the MLS-RP
interface
> > as an incoming ACL. That's it. This is where flow masks come into
play.
> > There are 4 situations that need to be considered when using ACLs and
> > Multilayer switching:
> >
> > 1) Where there is an incoming ACL on the MLS-RP interface, Multilayer
> > switching is out the window because every incoming packet must be
examined
> > by the router.
> >
> > 2) If there is no access list, you can use a Destination IP flow mask,
the
> > simplest of the flow masks, where only the destination IP address is
> looked
> > for in the MLS cache.
> >
> > 3) When there is a outgoing standard IP ACL applied to the MLS-RP
> interface,
> > a Source-Destination IP flow mask needs to be used. This forces the
> MLS-SE
> > to look for an entry with both the source and destination IP addresses
in
> > the MLS cache. Here's the reason why:
> >
> > If a packet has been sent from the MLS-SE to the MLS-RP, the packet gets
> > routed, then the outgoing ACL is applied. If the packet makes it back
to
> > the MLS-SE, then the MLS-SE knows that the packet was allowed (not
denied
> by
> > the ACL) and it makes a MLS cache entry. Since a standard IP ACL uses
> > source IP to permit/deny, the MLS-SE needs to look for the source IP as
> well
> > as the destination IP in the MLS cache. Any subsequent packets from/to
> the
> > same source/destination need not be compared to the ACL again as the
> > criteria for the ACL on the original packet was satisfied.
> >
> > 4) When there is an outgoing extended IP ACL applied to the MLS-RP
> > interface, an IP Flow mask needs to be used. An IP Flow masks instructs
> the
> > MLS-SE to look for an entry that contains the source IP and port AND
> > destination IP and port (basically Layers 3 AND 4). The MLS-SE must
look
> > for all of that information in the MLS cache because extended IP ACLs
> > permit/deny using all of those criteria. Again, the same reasoning
> applies
> > as far as the ACL goes, which is: if the first packet sent to the
MLS-RP
> > comes back to the MLS-SE, then the MLS-SE knows that the packet was
> allowed
> > (not denied) by the ACL, and therefore it doesn't need to check the ACL
> for
> > subsequent packet and Multilayer switching continues as normal.
> >
> > Most of the time an incoming ACL can be re-written as an outgoing ACL on
> > other interfaces. Although it is usually recommended to use incoming
ACLs
> > over outgoing ACLs (so that traffic unwanted traffic doesn't get into
the
> > router's fabric just to be denied going out of another interface), in
the
> > case of Multilayer switching, the disadvantages caused by using outgoing
> > ACLs are completely outweighed by the advantage of being able to use
> > Multilayer switching.
> >
> > So, even with an ACL active, as long as it's an outgoing ACL on the
MLS-RP
> > interface, "wire speed routing" is still in tact.
> >
> > > Anyhow, let routers do what they do best, and allow switches do their
> > > layer 2 stuff...
> >
> > Multilayer switching is an ingenious idea that allows a switch to take
an
> > incredible load off of the routers while not only providing the same
> > performance, but providing better, faster performance. As another post
> > mentioned, sure a router can do 100,000 packets/sec, but multilayer
> switches
> > can handle an order of magnitude more traffic (in the millions of
> > packets/sec)
> >
> > Mike W.
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=7508&t=7406
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