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CISCO ROUTER 2900

OthmaneMaissami
Level 1
Level 1

‎06-11-2020 10:02 AM

Hi

internet goes down in my network every day till I restart my cisco router 2900 series

when I checked the logs I found this :

 

Jun 8 13:43:18.116: %IP_VFR-4-FRAG_TABLE_OVERFLOW: Port-channel40: the fragment table has reached its maximum threshold 16
Jun 8 15:36:55.512: %IP_VFR-4-FRAG_TABLE_OVERFLOW: Port-channel40: the fragment table has reached its maximum threshold 16

 

is this the reason why the internet is dropping?

 the only youtube is opening

I have tried from all VLANs and almost all existing devices in the network same problem

the router is used as voice gateway also

thanks in advance

 

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6 Replies 6

Ayaz Baghirov
Level 1
Level 1

‎06-11-2020 11:09 AM

Hi,

Try to increase value X in option "ip virtual-reassembly max-reassemblies X" under the specific interface.

The range of X varies between 16 an 1024 if I am not mistaken.

Hope it helps!

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OthmaneMaissami
Level 1
Level 1
In response to Ayaz Baghirov

‎06-11-2020 04:41 PM - edited ‎06-11-2020 04:42 PM

Hi

Thanks for the reply

i did that before but i am still facing the same problem 

I need to restart the router every day

 

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Ayaz Baghirov
Level 1
Level 1
In response to OthmaneMaissami

‎06-12-2020 06:34 AM

Probably it can be a wrong value of MTU parameter on interfaces during configuration or someone/something  intentionally send fragmented packets to the interfaces.

 

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insideshell
Level 1
Level 1

‎06-12-2020 04:00 AM - edited ‎06-12-2020 04:07 AM

If you increased the value and it still happens, you'd better search why there are is too many IP fragmentation in your network. Can you post the relevant part of your configuration (i.e., downlink and uplink interfaces)?

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OthmaneMaissami
Level 1
Level 1
In response to insideshell

‎06-13-2020 10:07 AM

here is the reassembly count and the configuration of interfaces:

Compound_VGW#sh ip virtual-reassembly
GigabitEthernet0/1:
Virtual Fragment Reassembly (VFR) is ENABLED [in]
Concurrent reassemblies (max-reassemblies): 1024
Fragments per reassembly (max-fragments): 32
Reassembly timeout (timeout): 3 seconds
Drop fragments: OFF

Current reassembly count:0
Current fragment count:0
Total reassembly count:205
Total reassembly timeout count:0

Port-channel40:
Virtual Fragment Reassembly (VFR) is ENABLED [in]
Concurrent reassemblies (max-reassemblies): 1024
Fragments per reassembly (max-fragments): 32
Reassembly timeout (timeout): 3 seconds
Drop fragments: OFF

Current reassembly count:0
Current fragment count:0
Total reassembly count:449317
Total reassembly timeout count:311

 

 

 

interfaces conf :

Port-channel40 is up, line protocol is up
Internet address is 192.168.x.x/24
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is enabled
IP CEF switching turbo vector
IP Null turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is enabled, using route map INTERNET
Network address translation is enabled, interface in domain inside
BGP Policy Mapping is disabled
Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, Policy Routing, MCI Check
Output features: NAT Inside, Common Flow Table, Stateful Inspection, NAT ALG proxy
IPv4 WCCP Redirect outbound is disabled
IPv4 WCCP Redirect inbound is disabled
IPv4 WCCP Redirect exclude is disabled

 

 

 

 

Embedded-Service-Engine0/0 is initializing, line protocol is down
Internet protocol processing disabled
GigabitEthernet0/0 is up, line protocol is up
Internet protocol processing disabled
GigabitEthernet0/1 is up, line protocol is up
Internet address is 192.168.x.x/24
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
Split horizon is enabled
ICMP redirects are always sent
ICMP unreachables are always sent
ICMP mask replies are never sent
IP fast switching is enabled
IP fast switching on the same interface is disabled
IP Flow switching is disabled
IP CEF switching is enabled
IP CEF switching turbo vector
IP multicast fast switching is enabled
IP multicast distributed fast switching is disabled
IP route-cache flags are Fast, CEF
Router Discovery is disabled
IP output packet accounting is disabled
IP access violation accounting is disabled
TCP/IP header compression is disabled
RTP/IP header compression is disabled
Policy routing is disabled
Network address translation is enabled, interface in domain outside
BGP Policy Mapping is disabled
Input features: Common Flow Table, Stateful Inspection, Virtual Fragment Reassembly, Virtual Fragment Reassembly After IPSec Decryption, NAT Outside, MCI Check
Output features: Post-routing NAT Outside, Common Flow Table, Stateful Inspection, NAT ALG proxy
IPv4 WCCP Redirect outbound is disabled
IPv4 WCCP Redirect inbound is disabled
IPv4 WCCP Redirect exclude is disabled
GigabitEthernet0/2 is up, line protocol is up
Internet protocol processing disabled
Serial0/0/0:0 is down, line protocol is down
Internet protocol processing disabled
Serial0/0/0:1 is down, line protocol is down
Internet protocol processing disabled
Serial0/0/0:2 is down, line protocol is down
Internet protocol processing disabled
Serial0/0/0:3 is down, line protocol is down
Internet protocol processing disabled
Serial0/0/0:4 is down, line protocol is down
Internet protocol processing disabled
Serial0/0/0:5 is down, line protocol is down
Internet protocol processing disabled

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dendenden
Level 1
Level 1

‎11-19-2022 12:30 AM

Hi ,

I`m having the same issue, and even if I set the maximum reassembly threshold to 1024, it still reaches on that level which causes our 2901 router to increase its cpu util to 99% then thats the time vpn and sometimes internet traffic is affected. The only solution that we do now is to reboot the router and after sometime issue still happens again.

May I know how did u solve this problem brother?

Thank you

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