stds-80220-requirements: Questions and comments
I have a few questions on the current Rev 5 verison of the requirements
document
1- In section 3.2 we have a digram showing"MBWA interfaces". On the mobile
terminal end, why don't we have an IP Network. Or is the IP network on the
base station more properly titled "Internet"?
2- in section 4.1.8 "Number of Simultaneous Sessions" the author quotes a
number ">100". We need further qualification on that number. I see MAC
having two types of traffic. One that is time critical (Voice/streaming)
and one that can accept delays (data). So are we saying > 100 voice or > 100
of some combination. If it is some combination, we need to specify what the
ratio is.
3- In section 4.1.10 "Packet Error Rate", I assume that this requirement is
a layer 3+. If not, a 512 byte packet could be several air inteface PDUs.
(Look at Mark's recent proposal for the system diagram for a definition of a
PDU). 802.20 needs to define the error rate after FEC (if we are using
FEC). So do we need to create a derived requirement from this one?
4- In section 4.1.10 "Packet Error Rate", it states that the "... AI shall
use appropriate ARQ schemes...". I would suggest we say "...the AI shall
use error detection and error correction schemes..." I make this
suggestion, because PDUs with voice traffic will be sent. And if not
received correctly and it can not be corrected, the PDU will be discarded.
5- In 4.1.15.2 "Access Control" We should change the the whole paragraph to
be "A cryptographic method shall be used." For example a secured connection
using a certificate is not considered "challange-response". Also a
challange-response is at layer 7, not layer 2.
6-in 4.4.1 "quality of Service and the MAC", table 1 "Services and QoS
requirements" the last column says "Max Access Delay" is that over air link
only, all air links (assuming bridging over multiple links) or all links
(both land and air) in the path?
7- in 4.4.1.2, "Cos/Qos enforcement" , "error correction" (line 20), see my
comment #3 above
8- in 4.4.1.3, "ARQ/retransmision", see my comment #3 above
9- in 4.4.1.3, "ARQ/retransmision", line34-35 says "Dropped data segments
shall not hinder the timely delivery of any subsequent datagrams..." If you
are using ARQ, how can you get "dropped segments"? Or is the author stating
that data loss on one connection will not effect data transfer on another
simultanious connection?
10-4.4.1.4 "procotol support", it states IP Packet lengths of 46 to 1500.
An IP packet can be from 0 thru 2 to the 48 bytes long. The 46 to 1500 is
a function of the minimum/ maximum ethernet packet size. I am not sure if
the mac sees a smaller packet all the time, and does the MAC or LLC assemble
or segment the data.
10-4.4.1.4 "procotol support", line 4-5, the MAC does not know nor does it
care if the IP packet is part of a IPSEC stream. Again we have layer 3+ in
section 4.4.
11- in section 4.4.1.6 "support/optimizaton for TCP/IP, we have layer 3+ in
section 4.4.
a. chickinsky