Problem with link aggregation + sshd
ndenev at gmail.com
Wed Aug 29 12:33:01 UTC 2012
On Aug 29, 2012, at 1:18 PM, Harald Schmalzbauer <h.schmalzbauer at omnilan.de> wrote:
> schrieb Pete French am 29.08.2012 11:38 (localtime):
>>> Link aggregation can never work with two separate switches! LACP and
>>> static trunking require both sides to bundle the same trunk. which is
>>> impossible for two separate switches.
>> These switches had a port where you could connect them together and
>> then configure each to know about the other switch, and to do LACP
>> across the pair of them. Or at least thats what it looked like it
>> was capable of doing, and it appeared to be doing LACP when configured
>> that way and connected to Windows machines, just not FreeBSD ones. But I'm
> What you desciribe is well known as „stacking“ (not to mix with „virtual
> stacking“) and sorry that I haven't made clear that in such a case LACP
> (also static trunking of course) works well and is a fantastic way to
> gain redundancy.
> When you create a physical switch stack, the individual switches are no
> separate switches anymore, but act like one big switch.
> With the advantage, that in case of a failure, and a trunk configured
> over two different units of the stack, the link remains active.
> But like mentioned, these switches are then not considered to be
> separate („virtual stacking“ only combine them in management regards,
> _not_ physically, so be carefull when you look for switches with
> „stacking“ capabilities!).
> The disadvantage of the real hardware stackable switch is the price. The
> cheapest way I've found is two DGS-3120 (~700$ each plus 200$ stacking
> cable). Ciscos and Junipers and the bigger HPs are all much above afaik.
Not always. For example Extreme Networks's MLAG allows link aggregation between two switches, that
are not stacked. You just have to create a special vlan between them and configure them for MLAG.
But of course this is proprietary protocol.
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