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The Graveyard - Products No Longer Supported => Hubs and Switches => DGS-1216T => Topic started by: baumfalk on February 25, 2011, 12:22:54 AM

Title: DGS-1210-24 VLAN: Ethernet broadcast problems
Post by: baumfalk on February 25, 2011, 12:22:54 AM
Hi everybody,

I have three DGS-1210-24 in use, software version is 2.00.011 and each device is seperated into
4 VLANs (untagged):
VID    VLAN Name    Untagged VLAN Ports    Tagged VLAN Ports    VLAN Rename    Delete VID
1    Management A   01,02,03,04,05,06,07,08    
3    Data A   13,15,17,19,21,23
4    Data B   14,16,18,20,22,24
5    Management B   09,10,11,12

I have noticed that some (all?) Ethernet broadcast packets, which are injected over one VLAN (eg. VID 1) are routed to ALL other ports - even to ports which are not member of the same VLAN! (I have seen this behaviour with incoming LLDP packets, STP packets - STP was not enabled in the DGS-1210 at this time - and most probably also with CDP and DTP packets).

I my configuration - where 3 of these switches are connected to the same 4 network switches - this behavior leads to an unwanted packet storm, which is definitely not desired. (I had to switch off the unwanted multicasts at the source (3com) switch in order to avoid this problem, but of course it would reappear if a new source apperars somewhere in the network)

So my question: Is this a software bug or configuration problem and - most important - what can I do against it?

Best regards
Arno
Title: Re: DGS-1210-24 VLAN: Ethernet broadcast problems
Post by: nintendo1889 on March 23, 2013, 12:40:20 PM
If the broadcast came from 3com vlan 1 (untagged) it will be broadcasted through all other vlan 1 ports on the dlink (untagged or tagged). Same rule goes for vlan 2, 3 and so on (tagged).

Lookup the definition of 'ethernet broadcast domain'.
Title: Re: DGS-1210-24 VLAN: Ethernet broadcast problems
Post by: mrobcsi on January 09, 2014, 08:16:04 AM
Quote
If the broadcast came from 3com vlan 1 (untagged) it will be broadcasted through all other vlan 1 ports on the dlink (untagged). Same rule goes for vlan 2, 3 and so on (tagged).

Lookup the definition of 'ethernet broadcast domain'.

I believe he does know the definition of an Ethernet broadcast domain.  The issue is that these packets are being sent across broadcast domains.  I reported this issue with D-Link a couple of years back and they confirmed it in their lab.  Unfortunately, I don't believe that this switch will ever get the fix.