05-28-2019 02:25 PM
I have three switches connected in series. They are a 9300, a 2960 and a 4507. The 2960 is in the middle. The 2960 is connected to the 9300 by copper GB ports. The 2960 is connected to the 4507 by copper GB ports. All interconnecting ports are trunks. Encapsulation is ARPA. Distances are within 100 meters. Bandwidth and speed and duplex all match.
When I ping from the 2960 to the 9300, round trip time has little variation. It is between 1 MS and about 15 MS.
When I ping from the 2960 to the 4507, round trip time has extremely high variability. The minimum round trip time is 1 MS. The max round trip time is over 700 MS. There is no consistency from one second to the next.
Does anyone have any idea why there could be such high variation between the two connections? Any ideas as to how to correct it?
05-29-2019 12:16 AM
The Variaation have many reasons.
Some reasons :
1. Link satuaration.
2. Load on the device
3. how these devices connected.
So post some more information like configuration, and interface statistics, how your routing topolgy here?
05-29-2019 12:51 PM
The two switches are connected with a Cat 5 cable. I don't think the load on the link is close to capacity.
This is the interface in the 4507 that is connected to the 2960:
GigabitEthernet2/4 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet Port, address is 188b.9d7c.f573 (bia 188b.9d7c.f573)
Description: Link to IDF RM124 Switch
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 5/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 10/100/1000-TX
input flow-control is off, output flow-control is off
Auto-MDIX on (operational: on)
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output never, output hang never
Last clearing of "show interface" counters 1d05h
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 22209000 bits/sec, 3882 packets/sec
5 minute output rate 3295000 bits/sec, 1264 packets/sec
365959793 packets input, 253917723302 bytes, 0 no buffer
Received 24819753 broadcasts (960360 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
127899036 packets output, 44005896196 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
This is the interface in the 2960 that is connected to the 4507:
GigabitEthernet1/0/1 is up, line protocol is up (connected)
Hardware is Gigabit Ethernet, address is 2c73.a0d4.4301 (bia 2c73.a0d4.4301)
Description: Link to West Admin Core Switch
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 5/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
input flow-control is off, output flow-control is unsupported
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d05h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 4004
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 3056000 bits/sec, 1215 packets/sec
5 minute output rate 21202000 bits/sec, 3742 packets/sec
127963812 packets input, 43929819123 bytes, 0 no buffer
Received 5038399 broadcasts (2747701 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog, 2747701 multicast, 0 pause input
0 input packets with dribble condition detected
366714022 packets output, 254475446489 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier, 0 pause output
0 output buffer failures, 0 output buffers swapped out
This is the output of a ping between the two switches. The results show a lot of variability in reply times.
SUSIAHEAD001124#p i
Target IP address: 192.168.20.2
Repeat count [5]: 100
Datagram size [100]:
Timeout in seconds [2]:
Extended commands [n]: y
Source address or interface: 192.168.20.36
Type of service [0]:
Set DF bit in IP header? [no]:
Validate reply data? [no]:
Data pattern [0xABCD]:
Loose, Strict, Record, Timestamp, Verbose[none]:
Sweep range of sizes [n]:
Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 192.168.20.2, timeout is 2 seconds:
Packet sent with a source address of 192.168.20.36
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 1/29/577 ms
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