[LONG] Performance of an 877. How to increase the buffer?

First of all I'm sorry for the long post. I ran some tests with ping and you can see the output below.

Router#ping 195.210.91.83 size 1400 repeat 50 Sending 50, 1400-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!.!! Success rate is 68 percent (34/50), round-trip min/avg/max = 64/65/72 ms

Router#ping 195.210.91.83 size 1100 repeat 50 Sending 50, 1100-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !.!!.!!.!!.!!.!!.!!.!!.!!.!!.!!..!.!!.!!.!.!!.!!.! Success rate is 64 percent (32/50), round-trip min/avg/max = 56/56/64 ms

Router#ping 195.210.91.83 size 900 repeat 50 Sending 50, 900-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!!.!!!.!!!.!!!.!!!.!!!.!!!.!!!.!!!.!!!.!!!.!!!.!! Success rate is 76 percent (38/50), round-trip min/avg/max = 48/50/56 ms

Router#ping 195.210.91.83 size 700 repeat 50 Sending 50, 700-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!!!.!!!!.!!!!.!!!!.!!!!.!!!!.!!!!.!!!!.!!!!.!!!!. Success rate is 80 percent (40/50), round-trip min/avg/max = 40/41/52 ms

Router#ping 195.210.91.83 size 500 repeat 50 Sending 50, 500-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!!!!!.!!!!!!.!!!!!!.!!!!!!.!!!.!!!.!!!!!!.!!!!!!. Success rate is 84 percent (42/50), round-trip min/avg/max = 32/36/40 ms

Router#ping 195.210.91.83 size 300 repeat 50 Sending 50, 300-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!.!!!!!! Success rate is 92 percent (46/50), round-trip min/avg/max = 28/28/36 ms

Router#ping 195.210.91.83 size 150 repeat 50 Sending 50, 150-byte ICMP Echos to 195.210.91.83, timeout is 2 seconds: !!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!! Success rate is 96 percent (48/50), round-trip min/avg/max = 20/24/32 ms

As you can see the less the ICMP size is the less losses the router experiences. Can I work on the buffer on the ATM0.1 interface?

Which could be the option?

I ran the test in the opposite direction and I got no problems with any size of packets, hence I will choose the buffer for the packets leaving the router from ATM0.1 These are the values for the Vlan1 and ATM0.1 interfaces

interface ATM0.1 point-to-point ip address X.X.X.X 255.255.255.0 ip access-group 1 in ip mtu 1460 ip nat outside ip virtual-reassembly ip tcp adjust-mss 1440 pvc 8/35 oam-pvc manage encapsulation aal5snap ! end

interface Vlan1 ip address 10.10.10.254 255.255.255.224 ip access-group 199 in ip inspect ethernetin in ip nat inside ip virtual-reassembly ip tcp adjust-mss 1440 hold-queue 100 out end

I got the same results using MTU=1492 mss=1452 on ATM0.1

The ACL 1 cut off packets with not allowed sources (almost private addresses)

TIA

Alex

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Posted 5 years ago by AM in Cisco Systems

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