08-01-2021 03:33 PM
Hi, I am trying to configure LAG between SG-250-08 and C3560CG-8PC with the following topography:
+----+ +----+ |SRV1| |SRV2| +--+-+ +-+--+ GbE | | GbE | | +--+-------+--+ | C3560CG-8PC | +-----+-+-----+ | | 2xGbE LAG | | +-----+-+-----+ | SG-250-08 | +--+--------+-+ GbE | | GbE | | +--+-+ +--+-+ | PC1| |PC2 | +----+ +----+
The Cisco devices are connected with two cat6e cables, both devices have LAG configured and enabled, so the resulting channel should have a total bandwidth of 2Gbit.
I am testing the bandwidth between the following pairs using iperf: PC1 <=> SRV1 and PC2 <=> SRV2
According to my understanding of LAG, I should be able to see 1Gb between each pair.
Instead I see both pairs sharing 1Gb (500/500 Mbit roughly).
Here's the config for C3560CG-8PC
interface GigabitEthernet0/1 switchport mode access switchport access vlan 1 channel-group 1 mode active ! interface GigabitEthernet0/2 switchport mode access switchport access vlan 1 channel-group 1 mode active ! interface Port-Channel1 description UPLINK port-channel load-balance src-dst-mac
Port channel info
show interface po1 Port-channel1 is up, line protocol is up (connected) Hardware is EtherChannel, address is 80e8.6fe6.2d81 (bia 80e8.6fe6.2d81) Description: UPLINK MTU 1500 bytes, BW 2000000 Kbit/sec, DLY 10 usec, reliability 255/255, txload 1/255, rxload 7/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) Full-duplex, 1000Mb/s, link type is auto, media type is unknown input flow-control is off, output flow-control is unsupported Members in this channel: Gi0/1 Gi0/2 ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:01, output 00:03:17, output hang never Last clearing of "show interface" counters never Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: fifo Output queue: 0/40 (size/max) 5 minute input rate 56896000 bits/sec, 4682 packets/sec 5 minute output rate 293000 bits/sec, 527 packets/sec 2121328 packets input, 3219002211 bytes, 0 no buffer Received 242 broadcasts (236 multicasts) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 watchdog, 236 multicast, 0 pause input 0 input packets with dribble condition detected 240329 packets output, 16977081 bytes, 0 underruns 0 output errors, 0 collisions, 1 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
show etherchannel load-balance
EtherChannel Load-Balancing Configuration:
src-dst-mac
show lacp nei Flags: S - Device is requesting Slow LACPDUs F - Device is requesting Fast LACPDUs A - Device is in Active mode P - Device is in Passive mode Channel group 1 neighbors Partner's information: LACP port Admin Oper Port Port Port Flags Priority Dev ID Age key Key Number State Gi0/1 SA 1 a4b4.39bc.dde5 13s 0x0 0x3E8 0x8 0x3D Gi0/2 SA 1 a4b4.39bc.dde5 23s 0x0 0x3E8 0x7 0x3D
And for SG-250-08
interface GigabitEthernet7 channel-group 1 mode auto ! interface GigabitEthernet8 channel-group 1 mode auto ! interface Port-Channel1 flowcontrol on description UPLINK port-channel load-balance src-dst-mac
Port channel info
#show interface po1 Load balancing: src-dst-mac. Gathering information... Channel Ports ------- ----- Po1 Active: gi7-8
I tried with LACP enabled/disabled, same result.
When testing I see the LEDs on both ports blinking.
I just don't understand what I am doing wrong.
Solved! Go to Solution.
08-03-2021 11:57 AM
Found my problem - it's called too many open consoles and working after midnight. Instead of testing PC1-SRV1 and PC2-SRV2 I was testing from the same PC1 against SRV1 and SRV2 from two different consoles which lead to false measurements.
08-02-2021 02:36 AM
Nothing wrong here in the config ? But Load sharing based on the src-dest mac algorithm - you can find here:
https://www.cisco.com/c/en/us/support/docs/lan-switching/etherchannel/12023-4.html
Good post and explained here :
https://community.cisco.com/t5/switching/lag-speed-is-not-as-expected/m-p/2689038
Anothere test you can do is, what is the speeds SRV1 to SERV2 ? what is the speeds to PC1 to PC2 ?
08-03-2021 11:57 AM
Found my problem - it's called too many open consoles and working after midnight. Instead of testing PC1-SRV1 and PC2-SRV2 I was testing from the same PC1 against SRV1 and SRV2 from two different consoles which lead to false measurements.
08-04-2021 02:10 AM
Nice to know are you able to figureout the issue.
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