Need Some information on 4500 Series switches

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Jun 26th, 2009
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Hello Everyone ,

I need some information about the "Catalyst 4500 Series Switches" I was reading the "Data Sheet" for "4500 Series Switches" I have some confusion that is :

(1) What is 64 Gbps and 48 Mbps in 4500 Series Switches.

(2) Is there any formula to calculating "Bandwidth" and "Throughput"

(3) On "Data Sheet" it says "6 Gbps" and "24 Gbps" per slot bandwidth

( Suppose I have 48 port moduel it support 6 Gbps all together in classic or 24 Gbps in E- series")

(4) If any one know about the good link form where I can't find more detail about Catalyst 4500 Series switches please send me the e-mail , I am going to purchase the these switches very soon.

Please suggest

I have :

3550 as Main switch Qty #1

Speed 1000 MB

2924 swicthes Qty #3

switch support FastEthernt 100 MB(connecting to Test and Development servers)

2970 switches Qty # 2

switch support GigabitEthernt 1000 MB

(connecting to production servers)

3750 switches for users Qty # 5

switch support FastEthernt 100 MB

(Connecting to End Users)

"I have (2) 3750 switches stack together and other (3) switches stack together and both switches has only one trunk port to the main swicth that is "3550"

I don't know is the bandwidth isuue ?


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Giuseppe Larosa Fri, 06/26/2009 - 07:19
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Hello Muhammad,

real performance depends from all of the following:

chassis model

supervisor model

linecard types

total figure change widely


a comparison of supervisors

so 64 Gbps can represent a backplane capacity (equivalent to 32 GE full rate they count twice input/output)

48 Mpps stand for 48 millions of packets per second processed.


you need to take in account preamble and interframe gap:

given an IP packet of size S the line usage is given by:

S+18B = L2 frame

total usage = S+18B +20,2B

minimum size is 64 bytes padding is added if necessary

3) traditional linecards connect at 6 Gbps to the backplane but groups of 8 ports share a 1Gbps ASIC this is true up to WS-X4548-GB-RJ45 included

E modules have more performances

The choice of supervisor is dependent on the features you need to run be aware that last supervisors 6E 6LE can have more performance and less features then previous ones.

Hope to help


Joseph W. Doherty Fri, 06/26/2009 - 08:39
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#1 You're probably reading the supervisor's supported fabric bandwidth and forwarding rate.

#2 Yes there is, but depends on media and frame/packet sizes. Wire-rate or line-speed Ethernet requires about 1.488 Mpps per Gbps (one direction) for minimum size packets.

#3 The 6 Gbps vs. 24 Gbps, is how much bandwidth the chassis and supervisor can provide per card slot. To obtain up to 24 Gbps, you need a supervisor, chassis and line card that all can support it.


"I have (2) 3750 switches stack together and other (3) switches stack together and both switches has only one trunk port to the main swicth that is "3550"

I don't know is the bandwidth isuue ?

Not enough information to say, but you might be served well by using Etherchannel between some of the switches.

Unclear what you're needs are, especially L2 vs. L3, but if you want to consider a less expensive upgrade than a 4500 chassis, you might want to consider stacked 3750s and/or stacked 2975s. For instance, if your physical setup allowed it, adding two or three 3750Gs to your existing dual 3750s, to the same stack, might well eliminate the need for the other switches.


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