Trunking is unfortunately an over-used word, causing much confusion
in the world today... :(
Your reference to 802.1q leads me to believe you are talking about the
trunks that are defined 802.1q Annex D where you have multiple tagged
VLAN's configured on a single interface in order to pass traffic for
multiple VLAN's between two switches. All BIG-IP versions after v3.1
support tagged VLAN's (although I have to admit the support got *MUCH*
better after v4.x) and assigning multiple VLAN's to a single interface
for the purpose of VLAN trunking (that's what *I* call this use).
Although I'm confused by your reference to "bandwidth aggregation".
Rick has already replied to you referring to our "bigpipe trunk"
command, which is used to configure 802.1ad Link Aggregations, which
are used to make multiple links (physical ports) operate as a single
interface providing the sum of the bandwidths of the aggregated links
to the interface and also providing link failure protection (if one
of several aggregated links goes down, the others continue to operate).
One practical note is that, like most 802.1ad implementations, ours
works most efficiently if the number of interfaces configured is a
multiple of two. Another quirk of 802.1ad that is often not known
is that all packets associated with a single IP connection (say a
single telnet session) are *always* sent on the same link of an
aggregation (this is required by the spec). So, if you setup a
link aggregation, using 4 100BaseTX ports, and try to download a
single huge file via FTP, that single download will only be allowed
approximately 100Mb/s of bandwidth, but if you have a bunch of sessions
going simultaneously, you will see all four links utilized.
Before you ask, yes, you can configure a single set of links (say four
100BaseTX ports) to operate as an 802.1ad link aggregation (giving you
close to 400Mb/s of bandwidth on the interface) with multiple tagged
VLAN's going across that interface to another switch. One of our test
configurations uses four gigabit interfaces aggregated to a single
interface over which we pass traffic from four (two internal and two
external) VLAN's and it works like a charm. Link aggregation allows
you to use the full bandwidth capacity of your BIG-IP in a balanced
way when your traffic load is asymmetric (such as with web traffic
where the incoming requests are small, but the responses are large).
Hope this helps,
JMH
Tim Maestas wrote:
>
> I was wondering if anyone has had any experiences (good, bad, or
> otherwise) with using trunking under BigIP 4.x, in particular into a Cisco
> 6500 series switch. In reading the 4.x documentation, there is no mention
> of 802.1q trunk modes like there was in 3.x, so I'm not sure how I would
> be able to make my Cisco treat my trunked interfaces as a group. In 4.x
> it seems like outgoing packets from the BigIP would be
> "load-balanced" between the interfaces, but I don't see how this is
> possible for incoming packets, without something like 802.1q. Granted,
> if nothing else trunks will give me interface failover, but I'm looking
> more for bandwidth aggregation. Any info would be appreciated.
>
> -Tim
>
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