From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Thu Oct 27 2005 - 11:51:13 GMT-3
The "frame-relay tc" command is not used in FRTS from the client
side. See
http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_
guide09186a00800e955b.html for more detail.
As for the calculations for this solution they are as follows:
frame-relay cir 256000
This says to average 256000 bits per second. The question
states to use the lowest interval, which is 10ms. If you are sending
256000 bits every second, this means that you're sending 2560 bits every
10ms:
256000 bits | 1 second | 10 ms
Bc = -------------------------------- = 2560 bits
1 second | 1000 ms |
If you can only send 2560 bits in a single interval this means
that your largest packet fragment should be 2560 bits, or 320 bytes:
2560 bits | 1 byte
Fragment = -------------------- = 320 bytes
| 8 bits
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> Roberto Fernandez
> Sent: Wednesday, October 26, 2005 8:37 PM
> To: Cisco certification
> Subject: On Frame Relay fragmentation answer, IE lab 10
>
> Friends,
>
> In Lab #10, 9.1 to 9.4 from IE, frame relay fragmentation is required;
> after knowing the CIR (256K) and requiring the lowest Tc possible.
>
> The solution then uses
>
> map-class frame-relay DLCI_503
> frame-relay cir 256000
> frame-relay bc 2560
> frame-relay fragment 320
>
>
> I have the following questions,
>
> 1- Why specify Bc instead of Tc? (given the words "lowest shaping
> interval")
> 2- Why is fragment size 320 and not the Bc size?
>
>
>
> Best Regards,
> Roberto
>
>
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