3-Port Ethernet Switch with Self-Address Filtering - Page 1
Forum section: electronics / beginners

author: Timma
author_rank: Newbie
timestamp: March 05, 2022, 06:00:57 am
content: Hello.For a while have been using switches KSZ8873, KSZ8863, KSZ8463 from Micrel. Self-Address Filtering functionality is useful for HSR implementation. Now some of ICs are not recommended for new designs already.Is there any similar switches, another manufacturer probably?

author: SL4P
author_rank: Super Contributor
timestamp: March 07, 2022, 03:54:28 am
content: OK, I’ll bite.What is Self-Address Filtering

author: Timma
author_rank: Newbie
timestamp: March 10, 2022, 12:10:56 pm
content: Quote from: SL4P on March 07, 2022, 03:54:28 amProbably I used a wrong term.Here, explanation from the datasheet:

author: TomWinTejas
author_rank: Regular Contributor
timestamp: March 10, 2022, 05:56:50 pm
content: Does the Analog Devices fido2100 meet your requirements? The price is significantly higher than the Micrels, but it's the only one I see that has support for device level rings, which might offer the same functionality you are looking for?

author: Timma
author_rank: Newbie
timestamp: March 10, 2022, 06:28:04 pm
content: Quote from: TomWinTejas on March 10, 2022, 05:56:50 pmThanks, seems like FIDO2100 supports HSR.Though it doesn't have internal PHYs, which means 3 separate IC (one of them LQFP-128) instead of one LQFP-64. Will not fit on the board.Modern IC shortage is no jokeI wonder if Realtek chips have something similar?

author: magic
author_rank: Super Contributor
timestamp: March 11, 2022, 05:20:41 am
content: Some more sophisticated switches have VLAN support which is used by embedded systems like routers to pretend that some ports of the switch are different interfaces.The software would have to use different MACs on different VLANs (VLAN tags are stripped by the switch while forwarding the packet outwards) and in absence of filtering in the switch, it could detect looped packets itself by validating source MAC against VLAN tag added by the switch to ingress packets.

author: Timma
author_rank: Newbie
timestamp: March 11, 2022, 07:17:17 am
content: Quote from: magic on March 11, 2022, 05:20:41 amInteresting idea.Would that allow to use VLAN for its intended purpose?

author: magic
author_rank: Super Contributor
timestamp: March 11, 2022, 09:03:53 am
content: Not 100% sure.Apparently, you can nest VLANs (apply VLAN tags to already VLAN tagged frames).The question is if the switch will handle it normally or act up and if you can get your software to produce and receive such frames.See figure 4https://www.alliedtelesis.com/sites/default/files/documents/configuration-guides/c613-16016-00-a.pdfeditI may add that the whole filtering feature seems like a nothingburger to me, because host software could easily handle recognizing and ignoring packets originated from itself. I suppose what you really want is some ability to send packets through a chosen port and knowing which port the responses are coming through?

author: PKTKS
author_rank: Super Contributor
timestamp: March 11, 2022, 10:33:08 am
content: suggestion to move this to Networking...IMHO suchfeaturesare arguably cost effective...Paul

author: Timma
author_rank: Newbie
timestamp: March 11, 2022, 11:59:57 am
content: Quote from: magic on March 11, 2022, 09:03:53 amWell, if host takes on filtering all traffic in the net, it will require a lot of computing resources. More convenient when switch filters traffic and send to host only relevant packets.