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Posted by Miguel Sanders on August 10, 2008, 6:30 am
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> I don't know of any switch that supports the type of EtherChanneling you
> need. =A0How about installing 10Gb/s cards in the two servers and connect=
ing
> them back to back?
>
>
>
>
>
>
.
>
> >> > Hello all
>
> >> > I am currently using Cisco 3750E StackWise+ Switches. However, it
> >> > seems that this type of switch only supports layer 2 (MAC address -
> >> > src/dest/src and dest) and layer 3 (IP address- src/dest/src and des=
t)
> >> > hashing possibilities concerning EtherChannel load balancing. Is the=
re
> >> > an (affordable compared to the 3750E) switch available which support=
s
> >> > layer 4 (TCP port - src/dest/src and dest) etherchannel load
> >> > balancing?
>
> >> > Thanks a lot!
>
> >> > Miguel
>
> >> 4500 series minimum. Thats certainly more expensive the the 3700
> >> series.http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_n=
ote091...
>
> >> Is there a reason you specifically need layer 4? Only reason I really =
see
> >> is
> >> for it is multiple services on a server that are max'ing out, i.e emai=
l
> >> and
> >> web on a single server with email taking 100% of the bandwidth. If tha=
ts
> >> the
> >> case, it's cheaper just to add more servers and break out the services=
on
> >> to
> >> individual servers.
>
> >> -Brian
>
> > Well let me explain the background of this question:
>
> > Server A (TSM client) needs to backup to Server B (TSM server) over
> > Ethernet. Server A can have multiple TSM sessions to server B,
> > resulting in multiple tape mounts. Furthermore each TSM session
> > corresponds to one TCP session.
> > Server A and Server B both have a layer 4 EtherChannel defined of 4
> > interfaces in which the hashing is based on source and destination
> > ports.
> > So this means that, whenever Server A starts 2 TSM sessions to Server
> > B (=3D 2 TCP sessions resulting in 2 tape mounts), the EtherChannel on
> > server A will balance the load on two switchports (given the used
> > hashing algorithm). Unfortunately, since my 3750E only allows layer 2
> > and layer 3 EtherChannel load balancing, all load will be placed on
> > the same physical port of server B's EtherChannel, only resulting in a
> > maximum throughput of only 1 Gbit/s for server A. Ofcourse, whenever
> > another server (f.e. server C) starts a TCP session with server B, it
> > is likely (75% chance) that it will use another port of Server B's
> > EtherChannel...
> > Bottom line is that Server A will never get a bandwidth higher than 1
> > Gbit/s no matter how many TCP sessions is starts with Server B.
>
> > Do you understand the problem?
>
> > Thnx a lot!- Tekst uit oorspronkelijk bericht niet weergeven -
>
> - Tekst uit oorspronkelijk bericht weergeven -
If I look at the 4500 series, it is capable of examining the TCP
traffic and do load balancing based on src/destination TCP ports.
However, as already stated, this is an expensive solution and I think
I will look after something else.
Unfortunatele, the 10 Gbps ports are already used for uplinks.
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