Liang T. Wu
ltwu at faline.bellcore.com
Tue Aug 30 14:48:04 UTC 1994
I am sympathetic to your sentiment on the proposed RFC1490 approach to
build the NAPS particularly because so many people labored so hard to
come up with RFC 1577. However, as one of the person involved in the
NAP proposal, I would like to point out RFC 1483/1577 over AAL5 with
LLC/SNAP has always been our goal since at least one year ago. Given that
we have the same goal, it appears to me what you are objecting
to is the use of a temporary solution to meet the time table imposed on us.
Since changing the time table is not a viable option, I am
curious if you have other suggestions in mind? I am asking this question
just want to make sure that we did not miss anything significant in our
collective decision process.
> The difficulties with the RFC 1490 approach were listed in the
> Toronto meeting. I list them here:
> There is no clear migration path from this approach to
> a more correct/robust implementation using RFC 1577
> encapsulation over native ATM (OC3c).
My conversation with Cisco indicates that 1490/AAL5 software patch for
AIP is available and 1483/AAL5 for ADSU and 1483/AAL5 for T3-AIP should
be available withing about 6 months. So, indeed ther are several migration
path available, not clear which is the best for all NAPs. Perhaps different
NAP location may have different business needs based on what their customers
> There are additional points of failure and additional costs
> with the requirement for an ADSU.
I think HSSI is a proven technology. HSSI/ADSU probably has lower
failure rate than AIP based on the typical bath tub curb for new product
> The listed approach requires manual configuration.
I like the flexibility of AIP, but how to configure AIP to avoid congestion
is still a research topic for me.
> This appears to lock the NAP into a top speed of 45Mbps
> or DS3 speeds.
Hopefully, we can unlock this as soon as we feel comfortable with other
BTW, I think the Merit paper is useful and good work as you said. Since
RFC1490 is the only viable option exposed to Merit, saying it is one of those
is a bit too harsh.
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