Re: [rprsg] T&D Straw Poll #2 (discussion phase)
Hello Bob,
I would prefer the following terms:
Q1) ingress, egress - where ingress describes a packet entering the ring
from the MAC client, and egress describes a packet exiting the ring
(toward the MAC client). Since we are defining a MAC, we should be MAC-
centric in our terms for clarity.
Q2) no strong preference, other than not option (a) for reasons you have
outlined.
Q3) passthru
In general, I would suggest avoiding the SONET terms, since they have
become too value loaded, and may lead to confusion down the road for
those implementing RPR over SONET.
Thanks,
Allan.
Bob Sultan wrote:
>
> A key terminology issue has been the description of frames entering and
> leaving the ring from/to the MAC client, frames entering and leaving the
> station from/to the ring, and frames passing through the station while
> circulating on the ring. I have collected candidates for these terms
> (in three groups) below. Please post your additional candidate
> definitions and provide your comments on the T&D reflector. If there
> are no objections, I will conduct a straw poll starting at the end of
> day tomorrow (allowing discussion today and tomorrow). The straw poll
> is, of course, nonbinding.
>
> Q1) Terms describing frames entering the ring from the direction of the
> MAC client and exiting the ring towards the MAC client (respectively):
> a) ingress, egress
> b) ring ingress, ring egress
> c) entering, exiting
> d) add, drop
> e) insert, copy
> f) transmit, receive
> g) host transmit, host receive
>
> Q2) Terms describing frames received from the ring by a station and
> frames transmitted to the ring by a station (respectively):
> a) receive, transmit
> b) ring receive, ring transmit
> c) ring in, ring out (used by 802.5)
> d) inbound, outbound
> e) arriving, departing
>
> Q3) Terms describing frames transiting the station via the ring:
> a) transit
> b) thru
> c) passthru
> d) pass
> e) continue (used in combination with (add, drop) for consistency with
> SONET
> f) repeat (used by802.5)
>
> Some reasonable combinations might be:
> a) ingress, egress, ring-in, ring-out, repeat
> b) add, drop, inbound, outbound, continue
> c) insert, copy, ring receive, ring transmit, thru
>
> Some considerations:
>
> The terms 'transmit' and 'transit' look alike. After living with this
> for a while, I think the problem is real and I suggest that we don't use
> 'transit'.
>
> The terms 'transmit' / 'receive' are overloaded. They are used to
> indicate the placement / interpretation of signals on the medium AND the
> transfer of SDUs across protocol layers. It follows that these are not
> the best terms to distinguish ring circulating traffic from traffic
> to/from the MAC client. The terms could be qualified by 'host' /
> 'ring', but this has the potential for confusion.
>
> Cisco currently uses the terms 'ingress' / 'egress', but with the
> opposite orientation. For them, ingress traffic enters the router from
> the MAC and egress traffic exits the router towards the MAC (Cisco
> folks, did I get this right?). So, this may be confusing. On the other
> hand, this may not be a problem if there is agreement that 'ingress' /
> 'egress' are always understood to be relative to the layer of interest.
>
> If we wanted to be consistent with 802.5, I think we would be using
> (receive, transmit, ring-in, ring-out, repeat)... can the 802.5 experts
> confirm this?
>
> Bob