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Conference noted::atm

Title:atm
Moderator:NPSS::WATERS
Created:Mon Oct 05 1992
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:970
Total number of notes:3630

821.0. "LEC uses BUS until Data Direct VCC established?" by TKOV51::KATSUBE (Taiji Katsube, NPB-J) Mon Feb 10 1997 00:01

Question on our implementation of LEC(DECswitch 400 & ATMworks350).

Preceeding data packet sending, Data Direct VCC should be established
between the LECs. But it requires to send LEARP and wait for the reply,
so it takes a little time. While establishing the Data Direct VCC, 
how does the following LEC work ?
    Configuration:
	LE service - GIGAswitch/ATM
	LEC        - ATMworks350(Unix), DECswitch 400
a. discard packets form upper layer till the VCC is established
b. store the packets into a buffer
c. send packets via BUS using Multicast send VCC
If our implementation is 'c', the flash protocol is used when changing
the path from Multicast send VCC to Data Direct VCC?
T.RTitleUserPersonal
Name		DateLines
821.1SMURF::MENNERit's just a box of Pax..Mon Feb 10 1997 10:259
    Unfortunately there is a oversight (bug!) which never sends any
    unknown unicast addresses to the BUS.  This will be fixed in PTMIN
    (currently V4.0D).  But the fix will only send the first unknown
    frame to the BUS.  The Default value for this parameter is 1 to
    10 with a value of one recommended (currently shipping software
    uses zero).  
    
    And yes the flush protocol is always used when a new data direct
    is established.
821.2Packets are stored in buffers ?TKOV51::KATSUBETaiji Katsube, NPB-JWed Feb 12 1997 01:0713
>    Unfortunately there is a oversight (bug!) which never sends any
>    unknown unicast addresses to the BUS.  This will be fixed in PTMIN
>    (currently V4.0D).  But the fix will only send the first unknown
>    frame to the BUS.  The Default value for this parameter is 1 to
>    10 with a value of one recommended (currently shipping software
>    uses zero).  
    
It means that current LEC stores the packets into a buffer until the
Data Direct VCC is established ?

And how about DECswitch 400's LEC ? Same software with D-Unix is used
and has same bug ?
821.3SMURF::MENNERit's just a box of Pax..Thu Feb 13 1997 23:1011
>>It means that current LEC stores the packets into a buffer until the
>>Data Direct VCC is established ?
    
    No the packets are dropped.  It is assumed a higher layer protocol
    will resend them once the Data Direct VCC is established.

>>And how about DECswitch 400's LEC ? Same software with D-Unix is used
>>and has same bug ?
    
    Dunno