Here's the big question: What do you do about purchasing either hardware maintenance or on-site spares for that Customer Premises Equipment at both ends of the link?
It's not an easy answer (or I wouldn't have needed to write this article).
MAINTENANCE, SPARES, OR BOTH?
- Should you purchase maintenance on the equipment provided by the vendor?
- Should you purchase spare versions of the equipment?
- Should you do both?
FACTORS TO CONSIDER:
A number of factors must be taken into account when debating whether or not to purchase CPE maintenance.
Terms - Are the terms of the CPE maintenance reasonable, or are there multiple exclusions that would give the company an excuse to fail to deliver in accordance with the perceived SLA?
Equipment Criticality - Is the CPE serving a critical network link? Is there a backup link in case of failure?
Location - If the CPE will be located in a geographic area which is convenient to the network vendor's local parts depot, a CPE is very possibly warranted. If the CPE will be located in a remote area, a set of "warm spares" (duplicate CPE which has been preprogrammed to match the production CPE) kept at the CPE site is a better idea.
Cost of Replacement - How expensive is the CPE? The cost of CPE equipment has dropped steadily in recent years.
Trust of Response - How trustworthy is the vendor in terms of service delivery? Have you had a generally good or bad set of support experiences in the past?
Cost of Downtime - What function does the link in question serve? If this is a critical link, a set of warm spares is generally a good idea to ensure that the link be kept up at all times. (However, it should be noted, we suggest that especially critical network links should ideally have a backup link with automated link balancing/link failover.)
WHEN A SET OF SPARES IS BETTER:
In general, clients are better off purchasing CPE spares in situations where a network location is remote or difficult to access, and/or where a network link is so critical that a 2-, 4-, or 8-hour SLA to restore connectivity is insufficient to business needs.
Occasionally, we've worked with some clients who simply didn't have a high level of trust in their network vendor to provide adequate response, and purchased CPE spares for their own comfort.
Just purchasing the spares isn't enough, by the way. They need to be configured with a copy of the running configuration on the active equipment, so that the spare can be cold-swapped into place during a network outage. Each time the running configuration is updated, the spare needs to be updated.
A copy of the updated configuration should also be kept in electronic form somewhere on-site in case it needs to be reloaded into the spare (or original) equpiment.
WHEN MAINTENANCE IS BETTER:
Clients are better off purchasing CPE maintenance when there are insufficient internal technical resources to diagnose and/or swap out failed network components.
We have some clients who have purchased CPE maintenance simply to offload/outsource the exception handling of failed network equipment, whether or not the client maintained CPE spares.
WHEN YOU NEED BOTH SPARES AND MAINTENANCE:
For especially critical links, we have observed some clients utilize a "boots and suspenders" strategy, in which a CPE maintenance contract is paired with a set of onsite spares, as the network vendor's onsite engineer can make use of the spare more quickly than diverting to a parts depot on the way or leaving the client site to retrieve a spare from the local depot.
If a contract requires that CPE be purchased from the network vendor, we suggest that purchasing CPE maintenance is a good idea to eliminate the possibility of vendor "finger pointing" during link outages.
In this case, as outlined above, if a link is especially critical or there is doubt that the vendor may be able to replace CPE quickly in an emergency, we recommend purchasing spare CPE from the vendor, so there can be no question of the CPE's suitability or provenance.
HOW IMPORTANT IS THIS LINK?
Everything in this discussion boils down to: How critical is the link supported by the CPE?
The more critical the link, the higher the probability that a set of CPE spares is required in addition to maintenance.
There are cases where a given link may be critical but DOES have an automated balancing/failover mechanism in place. In these cases, a CPE maintenance contract may still be useful, specifically to provide vendor-executed replacement of bad equipment after the link has failed over, especially if there's no IT staff normally available to handle the situation.
If a link's function is critical enough to justify automated link balancing/failover, we suggest that the balancing/failover mechanism be designed and installed using a paired equipment configuration running in high-availability mode.
Finally, even when you have a high-availability configuration in place, keep in mind that a link balancing/failover mechanism can fail...and that's when having both maintenance and spares for equipment at each site can get your network link back up and running as quickly as possible.