As I gather, there is a mix of answers, ranging from "building the resources according to requirements and HOPE for the best" to "use of arguably sophisticated tools and perhaps sharing the results with the legal department".
I would be particularly interested in hearing the service providers' viewpoint on the following situation.
Consider a service provider with MPLS deployed within its own network.
(A) When the SP enters into a relation with the customer, does the SP establish new MPLS paths based on customer demands (this is perhaps similar to "building" based on requirements as pointed out by David)? If yes, between what sites/POPs? I assume the answer may be different depending upon a single-site customer or a customer with multiple sites.
(B) For entering into the relationship for providing X units of bandwidth (to another site of same customer or to the Tier-1 backbone), does the SP use any wisdom (in addition to MRTG and the likes)? If so, what scientific parameters are kept in mind?
(C) How does the customer figure out that a promise for X units of bandwidth is maintained by the SP? I believe customers may install some measuring tools but is that really the case in practice?
Thanks, Zartash
On Fri, Feb 20, 2009 at 1:16 AM, Stefan <netfortius@gmail.com> wrote:
Saqib Ilyas wrote:
Greetings I am curious to know about any tools/techniques that a service
uses to assess an SLA before signing it. That is to say, how does an administrator know if he/she can meet what he is promising. Is it
We use BRIX for SLA's by measuring round trip times, jitter, and packet loss across all of our backbone links. In conjunction with a traffic generator to add background traffic, and potentially invoke queueing on interfaces, we have found that BRIX enables us to accurately predict the behavior of new applications, particularly multicast and HD video, without the need to implement elaborate QoS configurations. BRIX is now owned by EXFO, a fiber optic test equipment manufacturer. Low values for rtt, jitter, and packet loss imply a relatively queue-free network, which makes confident predictions about network behavior easier. When we last looked at the technology, the Cisco IP SLA probes did not capture a random distribution of network events, as the probes are triggered every N minutes. BRIX randomizes the probes within a configurable window, so that, over time, all time intervals are covered by the accumulated probes. -----Original Message----- From: Saqib Ilyas [mailto:msaqib@gmail.com] Sent: Saturday, March 07, 2009 3:12 AM To: nanog@nanog.org Subject: Re: Network SLA I must thank everyone who has answered my queries. Just a couple more short questions. For instance, if one is using MRTG, and wants to check if we can meet a 1 Mbps end-to-end throughput between a couple of customer sites, I believe you would need to use some traffic generator tools, because MRTG merely imports counters from routers and plots them. Is that correct? We've heard of the BRIX active measurement tool in replies to my earlier email. Also, I've found Cisco IP SLA that also sends traffic into the service provider network and measures performance. How many people really use IP SLA feature? Thanks and best regards On Mon, Feb 23, 2009 at 1:19 PM, Zartash Uzmi <zartash@gmail.com> wrote: provider based on
experience? Are there commonly used tools for this? Thanks and best regards
Not necessarily as a direct answer (I am pretty sure there'll be others on this list giving details in the area of specific tools and standards), but I think this may be a question (especially considering your end result concern: *signing the SLA!) equally applicable to your legal department. In the environment we live, nowadays, the SLA could (should?!? ... unfortunately) be "refined" and (at the other end - i.e. receiving) "interpreted" by the lawyers, with possibly equal effects (mostly financial and as overall impact on the business) as the tools we (the technical people) would be using to measure latency, uptime, bandwidth, jitter, etc...
Stefan
-- Muhammad Saqib Ilyas PhD Student, Computer Science and Engineering Lahore University of Management Sciences