Timeline for Can I aggregate multiple uplink ports between Ethernet switches?
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
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| Jan 25, 2019 at 22:23 | vote | accept | Jason R | ||
| Jan 25, 2019 at 16:38 | comment | added | Ron Maupin♦ | @JasonR, OK I wanted to make sure that you understand that a carefully balanced traffic flow in one direction can be very unbalanced for return traffic. That really drives some people crazy, but it is a fact of life. Some people think that return traffic naturally follows the original path, but that simply isn't true for LAG frames, or even routed packets, as each is independently switched, regardless of any other frames or packets. | |
| Jan 25, 2019 at 16:28 | comment | added | Jason R | @RonMaupin that makes sense. For what it’s worth, in my case, the traffic is essentially unidirectional: a very high rate in one direction and little to none in the other. | |
| Jan 25, 2019 at 16:25 | history | edited | Zac67♦ | CC BY-SA 4.0 |
added 432 characters in body
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| Jan 25, 2019 at 16:25 | comment | added | Ron Maupin♦ | @JasonR, the traffic can also be asymmetric, and often is, even with the same hashing algorithm on both switches, because the source and destination addresses (both network and transport) are different in each direction. | |
| Jan 25, 2019 at 16:18 | comment | added | Zac67♦ | If you can choose the hashing scheme in a way that there can be no congestion you're set. However, most often you can't. LACP doesn't cover traffic distribution, only the aggregation by itself. Traffic distribution depends on the hardware at hand. | |
| Jan 25, 2019 at 16:06 | comment | added | Jason R | Thanks for the answer. I understand that I can't guarantee line rate between any pair of hosts at all times because there isn't enough uplink bandwidth (4x40-GbE) to support that. After reading about it some, it seems that the key will be choosing a good hashing scheme for our application so that flows get mapped to ports in the aggregation group in a way that minimizes the chance of oversubscription of any single port. From what I understand, this hashing scheme is defined in the group configuration, and the protocol doesn't provide a way to dynamically negotiate port usage? | |
| Jan 25, 2019 at 16:00 | history | answered | Zac67♦ | CC BY-SA 4.0 |