IPv6 on HP & 3Com unmanaged switch series

[lorn10]

Hi to all

I have the following question.

What's the current situation (in 2015) with the scope of IPv6 data traffic in conjunction with HP & 3Com unmanaged switches?

I know, on older unmanaged switches like the 3Com Baseline Switch 2824 series, IPv6 is officially NOT supported. This applies to many many other unmanaged HP & 3Com switches.

Well, - according to several sources I found on the web it seems that most Layer 2 devices should be regarding the IP version “agnostic”. So theoretically, for a simple Layer 2 switch it should be equal if IPv4 or IPv6 is used, - they only forward the corresponding Ethernet frames.

Does anyone have more information regarding this matter?

For example, the 3Com Baseline Switch 2824 series seems to be a pure Layer 2 device. There is no web UI, no VLAN, no higher Layer 3 feature present. Therefore, this switch should be IPv6 capable. Probably the overall IPv6 performance will be not great, - however if it works stable it will be fine for my use.

Should I try it? My primary (managed) switch is a 3Com 4800G one.

[Vince-Whirlwind]

If it is a Layer2 switch, then references to IPv6 support refer to the management addressing of that switch.

[lorn10]

Thanks Vince for this answer.

Well, most documentation / technical notes of older switches often do not mention any IPv6 related compatibility or incompatibility. Therefore it is difficult to interpret this lack of any IPv6 information.

A Layer 2 switch can work with IPv6, but it may also not function properly. Probably the age of the unmanaged switch is decisive. A ten year old unmanaged switch may have more problems than a six year old.

Back to my example, the (Layer 2) 3Com Switch 2824 is from 2008 and the documentation do not describe any IPv6 notes. The slight newer (Layer 3) 3Com Switch 2928 (also know as HP 1910-24G) is from 2009 and with latest firmware IPv6 compliant.

So there is a good chance that a 3Com Switch 2824 can also handle IPv6.

[Vince-Whirlwind · Accepted solution]

The Layer2 switch won't care what kind of Layer3 protocol is encapsulated in the ethernet frame - if the ethernet frame is a valid ethernet frame, all the Layer2 switch does is read the MAC addresses (and VLAN ID & IP Prec. in the case of an 802.1q frame) and forward the frame.

The Layer3 protocol in use can be Appletalk, IPv4, v6, IPX, DECNET, FCoE, or any one of numerous other types of Layer3 protocol - a Layer2 switch doesn't care.

So any talk about whether a Layer2 (only) switch supports IPv6 can only be referring to whether it can be configured with an IPv6 address for management.

Layer3 switches are different.

[lorn10]

Many thanks for this detailed response.

Now it’s clear, - IPv6 should be therefore not a problem for most (pure) unmanaged Layer 2 switches like the 3Com Switch 2824 is. Especially gigabit class unmanaged switches should be able to handle IPv6 correctly.

The real problem for most unmanaged switches is the handling of the 802.1Q (VLAN) feature. For example most unmanaged switches will drop “full-size 802.1q tagged frames” because these are exceeding the max (standard) buffer size of 1518 Byte, -full size tagged frames have 1522 Byte.

Well, regarding the 3Com Switch 2824, this series only supports the 802.1p standard, not the more complex successor 802.1Q.

So finally, unmanaged switches will work with IPv6 for simply use. But most of them will not understand any more complex handling of VLAN tags. In the best case they will forward them instead of droping them.

[Vince-Whirlwind]

My only experience with 2824s was ripping them out and throwing them in the bin, but I'm pretty sure they supported 802.1q...?

[lorn10]

I agree, for professional use you can forget the 3Com Baseline 28xx switch series. In a business environment you today simply need at least basic VLAN support. According to the data sheet attached below, the 3Com 28xx range switches only supports 802.1p which is a (not fully standardized) early form of 802.1Q.

As mentioned, our main “core” switch is a 3Com 4800G PoE (JD011A) which is near identical to the still available HP A5500-EI model. It’s a great device even all its features are totally overkill for us. :)

However, because near all of the 48 ports are now occupied, - I first think that I can simply connect a 3Com Baseline 2824 switch for all Non-PoE devices. Because of the missing VLAN support, and the resulting security vulnerability, I stop that idea.

Will now look for a managed 3Com 2928 Baseline switch, - it is the same like the HP 1910-24G Switch (JE006A). Like the 4800G it has a Comware firmware, - and naturally iPv6 and 802.1Q VLAN support. ;)