09-09-2015 03:31 AM - edited 03-05-2019 02:15 AM
Hi all,
I knew that 4948 switch is Layer 3 switch.
But I searched it through the Cisco web site ( http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-3750-x-series-switches/data_sheet_c78-584733.html )
There is a sentence it is Layer 2 to 4 ~ like below
he Cisco Catalyst® 4948 Switch is a wire-speed, low-latency, Layer 2 to 4, 1-rack-unit (1RU), fixed-configuration switch for rack-optimized server switching. Based on the proven Cisco® Catalyst 4500 Series hardware and software architecture, the Cisco Catalyst 4948 offers exceptional performance and reliability for low-density, multilayer aggregation of high-performance servers and workstations. High performance and scalability of intelligent network services is made possible with dedicated specialized resources known as ternary content addressable memory (TCAM). Ample TCAM resources (64,000 entries) enable high feature capacity, providing wire-speed routing and switching performance with concurrent provisioning of services such as quality of service (QoS) and security, and helping ensure scalability for today's network requirements with ample room for future growth.
The Cisco Catalyst 4948 offers 48 ports of wire-speed 10/100/1000BASE-T with four alternative wired ports that can accommodate optional 1000BASE-X Small Form-Factor Pluggable (SFP) optics.[1] Exceptional reliability and serviceability are delivered with optional internal AC or DC 1+1 hot-swappable power supplies and a hot-swappable fan tray with redundant fans (Figures 1 and 2).
Which reason does Cisco specify it Layer 4 switch..?
What is the difference among Layer 3 switches like WS-C3750E-24TD-E and ...
Thank you.
09-09-2015 07:05 AM
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Posting
I suspect that's because a 4948 might match on UDP and/or TCP ports numbers and process at wirespeed. (So might the 3750 series. The differences are, in other resources or features between the switch series. For example, the 4948 probably has more hardware buffering than the 3750 series and perhaps features like the 4500 series DBL.)
09-09-2015 04:21 PM
The meaning that buffering is higher quality than 3750 series.
So, can i understand RAM memory is high??
thank you
09-09-2015 04:36 PM
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Posting
Maybe, maybe not.
I believe switches have special high-speed RAM for interface buffers. I.e. it might not be the same RAM used by the IOS.
09-09-2015 09:29 PM
Thank you expert.
but I don't understand perfectly.One more question!
If I use Layer 4 function, can I use load balancing above the servers?..
09-10-2015 02:22 AM
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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
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Posting
I believe a 4948, like most Cisco L3 devices, when routing will CEF load balance by round robining "flows", and a flow, I also believe, considers L4 as an attribute.
09-10-2015 06:31 AM
Layer 4 is considered if the per-port algorithm has been selected (ip cef load-sharing algorithm include-ports ... ) otherwise a flow is just ip_source - ip_destination
Moreover in 4948 switch the include-ports option does not apply to the software-switched traffic.
Bye,
e
09-10-2015 07:35 AM
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The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
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In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Nice references! Thank you.
PS:
"Moreover in 4948 switch the include-ports option does not apply to the software-switched traffic."
If you're doing software switching - you got bigger problems. ;)
09-09-2015 07:14 AM
It means that has some feature that is based on layer 4 or higher. an example could be an ACL using TCP port
As far as forwarding is your concern a device could be layer 2 or layer 3, no more.
Bye,
enrico.
Please rate if useful
09-09-2015 04:18 PM
Thank you e.ciollaro!
I have another question
you wrote down 4948 support ACL with TCP.
maybe its fuction is also supported by Router right?
I wonder whether I understand exactly .
Regards,
09-10-2015 06:18 AM
Hi,
yes, router can match at layer 4 too (protocol and port)
For more information about L4 ACL look at this:
Bye,
e
PS please rate if useful
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