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Narbik,

It is definitely great to know what frame-relay fragmentation does and to see how it affects traffic sent thru it. I think that your example is great for that. But the question is to know when it is necessary. Most tasks are not specifically going to tell a student to do fragmentation but the student needs to understand based on the requirements of the question that they need to do it.

But really that was a great example of configuring it Narbik.

Regards,

Tyson Scott - CCIE #13513 R&S and Security
Technical Instructor - IPexpert, Inc.
Telephone: +1.810.326.1444 Cell: +1.248.504.7309 Fax: +1.810.454.0130 Mailto: tscott@ipexpert.com

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From: Narbik Kocharians [mailto:narbikk@gmail.com] Sent: Monday, January 12, 2009 3:34 PM To: Pavel Bykov Cc: Tyson Scott; Hobbs; mike jones; ccielab@groupstudy.com Subject: Re: Frame-relay Fragmentation!

You should NOT look for words, you should focus on knowing what it does and where to use it and how and where it helps.

The topology is as follows:

R1—S0/0–10.1.12.1/24—————–Frame-relay——————–10.1. 12.2/24–S0/0—-R2

R1’s Loopback is 1.1.1.1/8
R2’s Loopback is 2.2.2.2/8

Task 1

Configure Frame-relay Fragmentation between the two routers such that the largest packet size is 80 Bytes.

On Both Routers:

Rx(config)#interface S0/0
Rx(config-if)#Frame-relay fragment 80 end-to-end

To verify the configuration:

On R1

R1#Show frame-relay pvc 102

PVC Statistics for interface Serial1/0 (Frame Relay DTE)

DLCI = 102, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

input pkts 0 output pkts 0 in bytes 0
out bytes 0 dropped pkts 0 in pkts dropped 0
out pkts dropped 0 out bytes dropped 0
in FECN pkts 0 in BECN pkts 0 out FECN pkts 0
out BECN pkts 0 in DE pkts 0 out DE pkts 0
out bcast pkts 0 out bcast bytes 0
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
pvc create time 00:29:43, last time pvc status changed 00:28:34
fragment type end-to-end fragment size 80

Note the output of the above show command reveals that Frame-relay fragmentation is enabled and the type is set to end-to-end which is FRF.12

To test the configuration:

On R1

R1#Ping 10.1.12.2 size 80 repeat 1

Type escape sequence to abort.
Sending 1, 80-byte ICMP Echos to 10.1.12.2, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 64/64/64 ms

R1#Show frame-relay fragment 102

interface dlci frag-type size in-frag out-frag dropped-frag
Se0/0 102 end-to-end 80 2 2 0

Note the fragmentation size is set to 80 Bytes, and the size of the ping packet was 80 Bytes as well, but the output of the above show command reveals that there were two fragmented packets. This is because the size of the frame-relay header was NOT considered when the size of the ping packet was configured. The actual size of the frame-relay header is 2 Bytes, and as a result of that, the size of the ping packet was 82 Bytes, therefore, 2 fragmented packets were generated.

To test this further:

On R1

R1#clear counters

Clear “show interface” counters on all interfaces [confirm]
R1#

R1#Ping 10.1.12.2 size 78 repeat 1

Type escape sequence to abort.
Sending 1, 78-byte ICMP Echos to 10.1.12.2, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 40/40/40 ms
R1#

R1#Show frame-relay fragment 102

interface dlci frag-type size in-frag out-frag dropped-frag
Se0/0 102 end-to-end 80 0 0 0

Note the above Show command reveals that the ICMP packet was NOT fragmented; the size of the ICMP packet is 78 Bytes plus the two Bytes of Frame-relay header equals to 80 Bytes, therefore, it does not need to get fragmented.

To test the configuration further:

On R1

R1#Ping 10.1.12.2 size 79 repeat 1

Type escape sequence to abort.
Sending 1, 79-byte ICMP Echos to 10.1.12.2, timeout is 2 seconds:
!
Success rate is 100 percent (1/1), round-trip min/avg/max = 60/60/60 ms

R1#Show frame-relay fragment 102

interface dlci frag-type size in-frag out-frag dropped-frag
Se0/0 102 end-to-end 80 2 2 0
R1#
i hope this helped.
On Mon, Jan 12, 2009 at 11:21 AM, Pavel Bykov wrote:
Also look for “Large data packets” and “voice packets are prioritized although are waiting behind large packets that take long to send out”
Tyson, correction: Reducing delay, since there is no way to prevent it

On Mon, Jan 12, 2009 at 7:21 PM, Tyson Scott wrote:
> Mike, > > Or if the question talks about preventing serialization delay. > > Regards, > > Tyson Scott - CCIE #13513 R&S and Security > Technical Instructor - IPexpert, Inc. > > Telephone: +1.810.326.1444 > Cell: +1.248.504.7309 > Fax: +1.810.454.0130 > Mailto: tscott@ipexpert.com > > > > —–Original Message—– > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of > Hobbs > Sent: Monday, January 12, 2009 11:54 AM > To: mike jones > Cc: ccielab@groupstudy.com > Subject: Re: Frame-relay Fragmentation! > > Off the top of my head, maybe something like “maximum packet size”… > > On Mon, Jan 12, 2009 at 9:50 AM, mike jones > wrote: > > > Group, > > What key words in a tasks will lead you to frame-relay fragmentation > as > > the solution? > > > > > > > > > > > > Thanks! > > > > > > Mike > > > > _________________________________________________________________ > > Windows Live : Keep your life in sync. > > http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009 > > > > > > Blogs and organic groups at http://www.ccie.net > > > > _______________________________________________________________________ > > Subscription information may be found at: > > http://www.groupstudy.com/list/CCIELab.html > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html > > > Blogs and organic groups at http://www.ccie.net > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html > > > > > > > >

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