Re: cut-through switching method

Ah that's right. If you are using FCoE the port-to-port delay is VERY
important to compare to FC switches. That is the reason for changing
this behavior. The security that store and forward delivers has now
been brought a layer up to the FC layer. Besides that the Nexus 5000
is positioned as top-of-rack or end-of-row switch. Therefor you can
use the twinax cables (SFP+ to SFP+ cables) which have a very low loss.

--
Regards,
Rick Mur
CCIE2 #21946 (R&S / Service Provider)
Sr. Support Engineer  IPexpert, Inc.
URL: http://www.IPexpert.com
On 4 nov 2009, at 22:52, Cristian Matei wrote:
> Hi,
>
> Actually, for example, Nexus 5000 Series is using cut-through
> technology;
> also some metro switches like 4900 have a low-latency ASIC design
> but still
> use store-and-forward.
>
> Regards,
> Cristian.
>
> -----Original Message-----
> From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf
> Of
> Anantha Subramanian Natarajan
> Sent: Wednesday, November 04, 2009 11:40 PM
> To: Rick Mur
> Cc: Cisco certification
> Subject: Re: cut-through switching method
>
> Great and thanks for clarifying rick
>
> Regards
> Anantha Subramanian Natarajan
>
> On Wed, Nov 4, 2009 at 3:38 PM, Rick Mur <rmur_at_ipexpert.com> wrote:
>
>> Since the performance of the current switches is so good it's
>> totally not
>> needed to change the switching method as it will not improve any
> performance
>> and will only bring you more trouble, because the chance of  bad
>> frames is
>> bigger.
>>
>> Therefore it's also not possible to change. All switches now use
>> the store
>> and forward switching mechanism.
>>
>>
>>
>>
>> --
>> Regards,
>>
>> Rick Mur
>> CCIE2 #21946 (R&S / Service Provider)
>> Sr. Support Engineer  IPexpert, Inc.
>> URL: http://www.IPexpert.com
>>
>> On 4 nov 2009, at 21:16, Anantha Subramanian Natarajan wrote:
>>
>> Hi All,
>>
>> I have a basic question on switching method on cisco switches. My
>> understanding is,in the cisco switches the default method of
>> switching
>> packets is store and forward,kindly correct me if that is wrong.Is
>> there a
>> command to change it to cut-through method in cisco 3750 switches
>> and also
>> how we verify the same from the show command.
>>
>> Thank You for the great help
>>
>> Regards
>> Anantha Subramanian Natarajan
>>
>>
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