[c-nsp] SLAs on a Gigabit Ethernet link

[Adam Greene]

Well, it figures that someone else posted information related to these
questions 45 minutes before my note, and I didn't read it (Jee Kay, "IP SLA
/ rtr MIA strangeness").

I see that the 3560G's do support IP SLAs, but using the pre-12.3 "rtr"
commands.

The conceptual questions about how to guarantee / measure bandwidth capacity
via SLAs still stand.

Thanks,
Adam


----- Original Message ----- 
From: "Adam Greene" <maillist at webjogger.net>
To: <cisco-nsp at puck.nether.net>
Sent: Monday, September 18, 2006 5:23 PM
Subject: [c-nsp] SLAs on a Gigabit Ethernet link


> Hi,
>
> Perhaps this is asking a lot, but if anyone is able to point me in the
right
> direction or provide some good summary answers, I'd be grateful.
>
> I need to generate a Service Level Agreement for a customer that we're
going
> to be providing a point-to-point link for. On either end of the link will
be
> a 3560G. The link will actually be wireless, via Gigabit radios, but
that's
> not so relevant. We'll be connecting two branches of a Radiology
department.
> They plan to pass large MRI files between the two locations.
>
> First off, I am trying to figure out how to conceptualize the SLA. Network
> availability is a no-brainer (the link passes traffic or it doesn't).
> However, the customer wants to be sure that the link is always performing
> well, and that the maximum bandwidth capacity of the link is always
> available to him.
>
> I'm thinking of making use of Cisco's IP SLAs functionality to monitor any
> performance guarantees I may make to the customer.
>
> Some questions:
> -    do the 3560G's even support IP SLAs? According to CCO, all IOS
supports
> it (except for some obscure exceptions), but I don't find any reference to
> it in the 3560 configuration guide, and when I grope around on a 3750 in
the
> lab, the switch seems not to support SLAs ("sh ip sla" is an unknown
> command; "ip sla ..." is an unknown configuration command)
> -    it seems that the UDP jitter operation could be a good way to get
> information about packet loss and latency on the link. However, I'm not
sure
> that obtaining these values will necessarily enable me to provide the
> customer with exactly what he needs. The customer needs to know that the
> link supports up to 1Gbps of data traffic (minus any overhead) at all
times;
> if the customer himself is maxing out the link and I measure latency and
> packet loss, the results could appear poor. On the contrary, though, the
> link would be doing exactly what it is supposed to be doing: passing
~1Gbps
> traffic.
>
> Perhaps one way to approach monitoring of the SLA could be to continuously
> graph the utilization of the link and then associate the utilization
values
> to the packet loss and latency at any given moment. But then it seems that
I
> would need an algorithm of some kind to determine what acceptable latency
> and packet loss are on a 1Gbps link at varying traffic loads.
>
> Does anyone have any tips about how to approach these issues?
>
> Thanks,
> Adam
>
>
>
>
>
>
>
>
>
>
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