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%IP_VFR-3-COALESCE_ERROR: Unable to coalesce fragments arriving through FastEthernet0/0 - datagram 8220 bytes is too big.

prashantrecon
Level 1
Level 1

HI All

I have  excuted the command

ip virtual-reassembly max-reassemblies 64 under the interface.

still we are facing the issue

10 Replies 10

Pulkit Nagpal
Cisco Employee
Cisco Employee

Hi Prashant,

looking at the log message, this seems to be similar to bug: CSCsr59225. According to this bug:

Symptom:


Fragmented packets may trigger the following tracebacks on IOS routers:


Jul 26 00:24:00.484: %SYS-2-GETBUF: Bad getbuffer, bytes= 35040 -Process= "

", ipl= 2, -Traceback= 0x80845F4C 0x8030D5D4 0x810227F0 0x81023440 0x81023DA4 0x8005E51C 0x80054C2C 0x8011B1DC 0x8011CF54 0x8036A0C4 0x800C0BD0 0x800C0BD0 0x8036A184 0x8036D2C8 0x8036CD84 0x80375E5C
router#
Jul 26 00:24:00.484: %IP_VFR-3-SYSTEM_ERROR: FastEthernet4: IP VFR System failure - Unable to coalesce fragments

Conditions:

The router is configured with "ip virtual-reassembly" and receives large fragmented segments.

Workaround:

Use the following command to configure the size of the huge buffer large enough such that these large packets can be coalesced:

buffers huge size

The size should be set such that it is larger than the number of bytes reported in the SYS-2-GETBUF message.

Please note that this workaround may have an impact on memory usage.

Please see if your IOS is one of the affected IOS.

Please mark this post answered if you you think your query has been solved.

Regards,

Pulkit Nagpal

Hi Pulkit,

Please find the ios version of router

Cisco IOS Software, 2800 Software (C2800NM-IPBASEK9-M), Version 12.4(24)T1, RELE                                                                             ASE SOFTWARE (fc3)

how to check buffer size assigned

when i excuted the command show buffres all i got the following output

4411F690 3F842004 Small    0    60    0    0        0           None        None

4412026C 3F84B784 Large    0     0    0    0        0           None        None

44135B00 3F8433C4 Small    0    60    0    0        0           None        None

44393CC0 3F400BA4 Small    1     0    0    0        0           None        None

44394094 3F400CE4 Small    0    60    0    0        0           None        None

44394468 3F400E24 Small    1    60    7    1       80           None        None

4439483C 3F400F64 Small    0    60    0    0        0           None        None

44394C10 3F4010A4 Small    0    60    0    0        0           None        None

44394FE4 3F4011E4 Small    0    60    0    0        0           None        None

443953B8 3F401324 Small    0    87    0    0        0           None        None

4439578C 3F401464 Small    0    85    0    0        0           None        None

44395B60 3F4015A4 Small    0    60    0    0        0           None        None

44395F34 3F4016E4 Small    0    60    0    0        0           None        None

44396308 3F401824 Small    0    60    0    0        0           None        None

443966DC 3F401964 Small    0    85    0    0        0           None        None

44396AB0 3F401AA4 Small    0    87    0    0        0           None        None

44396E84 3F401BE4 Small    0    60    0    0        0           None        None

44397258 3F401D24 Small    0    85    0    0        0           None        None

4439762C 3F401E64 Small    0    85    0    0        0           None        None

44397A00 3F401FA4 Small    0    73    0    0        0           None        None

44397DD4 3F4020E4 Small    0    60    0    0        0           None        None

443981A8 3F402224 Small    0    60    0    0        0           None        None

4439857C 3F402364 Small    0    60    0    0        0           None        None

44398950 3F4024A4 Small    0    60    0    0        0           None        None

44398D24 3F4025E4 Small    0    60    0    0        0           None        None

443990F8 3F402724 Small    0    85    0    0        0           None        None

443994CC 3F402864 Small    0    85    0    0        0           None        None

443998A0 3F4029A4 Small    0    60    0    0        0           None        None

44399C74 3F402AE4 Middl    0   614    0    0        0           None        None

4439A048 3F402E24 Middl    0   512    0    0        0           None        None

4439A41C 3F403164 Middl    1   614    7    1        0           None       Fa0/0

4439A7F0 3F4034A4 Middl    1   614    7    1        0           None       Fa0/0

4439ABC4 3F4037E4 Middl    0   614    0    0        0           None        None

4439AF98 3F403B24 Middl    1   614    7    1        0           None       Fa0/0

4439B36C 3F403E64 Middl    0   132    0    0        0           None        None

4439B740 3F4041A4 Middl    0   614    0    0        0           None        None

4439BB14 3F4044E4 Middl    1    60    7    1        0           None       Fa0/0

4439BEE8 3F404824 Middl    0   132    0    0        0           None        None

4439C2BC 3F404B64 Middl    0   149    0    0        0           None        None

4439C690 3F404EA4 Middl    0   614    0    0        0           None        None

4439CA64 3F4051E4 Middl    0   132    0    0        0           None        None

4439CE38 3F405524 Middl    0   614    0    0        0           None        None

4439D20C 3F405864 Middl    0   614    0    0        0           None        None

4439D5E0 3F405BA4   Big    0    87    0    0        0           None        None

4439D9B4 3F406284   Big    0    87    0    0        0           None        None

4439DD88 3F406964   Big    0    86    0    0        0           None        None

4439E15C 3F407044   Big    0    92    0    0        0           None        None

4439E530 3F407724   Big    0    86    0    0        0           None        None

443F83B8 3F407E04   IPC    0     0    0    0        0           None        None

443F878C 3F408EE4   IPC    0     0    0    0        0           None        None

443FDC84 3F409FC4   IPC    0     0    0    0        0           None        None

You need to check show buffers for this, see below:

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a7b80.shtml

12.4(24) is one of the affected versions however, before you decide to upgrade your router you can use the workaround to see if this solves the issue for you.

Regards,

Pulkit

Hi Pulkit

For the inside interface the output  for buffer is

FastEthernet0/0 buffers, 1536 bytes (total 384, permanent 384):

     0 in free list (0 min, 384 max allowed)

     384 hits, 0 fallbacks

     384 max cache size, 256 in cache

     206778656 hits in cache, 0 misses in cache

so looking at above output 384 buffer are in router and there are 0 in free list.

so shall i need to increase it

Hi Prashant,

In my last reply , i asked you to check output of "show buffers" , can you please check:

show buffers

& before increasing buffer size, please check sh memory to see the available memory

Pulkit

Router#show buffers

Buffer elements:

     688 in free list (1119 max allowed)

     9346983 hits, 0 misses, 619 created

Public buffer pools:

Small buffers, 104 bytes (total 108, permanent 50, peak 149 @ 3d06h):

     104 in free list (20 min, 150 max allowed)

     2511885 hits, 2085 misses, 1578 trims, 1636 created

     669 failures (0 no memory)

Middle buffers, 600 bytes (total 25, permanent 25, peak 37 @ 5d06h):

     23 in free list (10 min, 150 max allowed)

     166869 hits, 247 misses, 128 trims, 128 created

     138 failures (0 no memory)

Big buffers, 1536 bytes (total 50, permanent 50, peak 192 @ 5d04h):

     50 in free list (5 min, 150 max allowed)

     3962291 hits, 3790 misses, 393 trims, 393 created

     3420 failures (0 no memory)

VeryBig buffers, 4520 bytes (total 10, permanent 10, peak 51 @ 5d04h):

     10 in free list (0 min, 100 max allowed)

     1790 hits, 1714 misses, 41 trims, 41 created

     1714 failures (0 no memory)

Large buffers, 5024 bytes (total 1, permanent 0, peak 11 @ 5d05h):

     1 in free list (0 min, 10 max allowed)

     364 hits, 1354 misses, 79 trims, 80 created

     1354 failures (0 no memory)

Huge buffers, 18024 bytes (total 1, permanent 0, peak 6 @ 5d05h):

     1 in free list (0 min, 4 max allowed)

     628 hits, 849 misses, 62 trims, 63 created

     849 failures (0 no memory)

Interface buffer pools:

CD2430 I/O buffers, 1536 bytes (total 0, permanent 0):

     0 in free list (0 min, 0 max allowed)

     0 hits, 0 fallbacks

IPC buffers, 4096 bytes (total 140, permanent 140):

     140 in free list (70 min, 280 max allowed)

     0 hits, 0 fallbacks, 0 trims, 0 created

     0 failures (0 no memory)

Header pools:

Header buffers, 0 bytes (total 768, permanent 768):

     256 in free list (128 min, 1024 max allowed)

     512 hits, 0 misses, 0 trims, 0 created

     0 failures (0 no memory)

     512 max cache size, 512 in cache

     36692 hits in cache, 0 misses in cache

Particle Clones:

     1022 clones, 115056 hits, 0 misses

Public particle pools:

F/S buffers, 256 bytes (total 768, permanent 768):

     256 in free list (128 min, 1024 max allowed)

     512 hits, 0 misses, 0 trims, 0 created

     0 failures (0 no memory)

     512 max cache size, 512 in cache

     0 hits in cache, 0 misses in cache

Normal buffers, 1548 bytes (total 768, permanent 768):

     768 in free list (128 min, 1024 max allowed)

Cisco 2811 (revision 53.51) with 249856K/12288K bytes of memory.

Processor board ID FHK1212F295

4 FastEthernet interfaces

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

Router-# show memory

                Head    Total(b)     Used(b)     Free(b)   Lowest(b)  Largest(b)

Processor   4411F660   187566496    29909656   157656840   156503440   151005996

      I/O   3F400000    12582912     4488536     8094376     7570288     8060092

You can see:

Huge buffers, 18024 bytes (total 1, permanent 0, peak 6 @ 5d05h):

    1 in free list (0 min, 4 max allowed)

     628 hits, 849 misses, 62 trims, 63 created

     849 failures (0 no memory)

I think you can try the workaround given that you have enough I/O memory available.

Regards,

Pulkit

Hello Prashant,

If you think this question has been answered, can you please mark this as answered? This will help others as well.

Regards,

Pulkit

Hi Pulkit,

I am still working on it .if possible can you please share an example to increase huge buffer size.

Regards,

Prashant

Hi Prashant,

Here is a good document on buffer tuning:

http://www.cisco.com/en/US/partner/products/hw/routers/ps133/products_tech_note09186a00800a7b80.shtml#buffer_tuning

However if you are not confident about the tunning i recommend against it as tunning these buffers manually reduces the router's ability to dynamically adjust. Which in turn will cause more bad than good.

Better you upgrade to a version which is not affected by this bug.

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