Conference netcad::hub_mgnt

437.0. "DECMR questions" by NMOSPD::SYSTEM () Mon Oct 18 1993 12:27

      7
  Hi, here is the customer network configuration, with NFS implemented 
  between Hp workstation and DECworkstation.

  The DEC5240 exports one cad drawing file system to HP machines.

	CUSTOMER  CONFIGURATION:
________________________________________________________________________________

		   Fiber Optic to backbone (4 VAXes 1 ALPHA 10 Terminal Server)
				/
	   DEChub 90 	       /
	      [T]             /
	----------------     /
	| 		|   /
	| Power supply  |  /
	----------------- /  --------   --------  --------  ---------
	| Slot 8 DEWGB	|/  |DEC5240 | |DEC5133 ||DEC5133 || DEC5133 |
	-----------------    ________ 	________  ________  _________	
	| Slot 7 DECMR  |	|          |          |         |        
	|    Port 5 ----|----------------------------------------------[T]
	| Port 6 -------|--------
	-----------------	|    -------	  
	| Slot 6  empty |	|---| HP710 |HPUX A.08.07 A
	-----------------	|    -------
	| Slot 5 empty	|	|
	-----------------	|    ------
	| Slot 4 DSRVG	|	|---| HP720| HPUX A.B8.05 A
	-----------------	|    ------
	| Slot 3 DSRVG	|	|
	-----------------	|
	| Slot 2 DSRVG	|	|    ------------	
	-----------------	|---| HP9000/345 | HPUX 7.05 B
	| Slot 1 DSRVG	|	|    ------------
	----------------- 	|
				|
				|    ------------
				|---| HP9000/345 | HPUX 7.05 B
				|    ------------
				|
				|
				|    ------------
				|---| HP9000/360 | HPUX 7.05 B
				|    ------------
				|
				|
				|
				|   -----------	
				|   |         |
				|---|APOLLO   | [PRIVATE APOLLO NETWORK]
				|   |	WSTAT.|-----------------------   
				|   |---------	
			       [T]	


	CUSTOMER PROBLEM AND WORKAROUND:
  ________________________________________________

 Using this network topology, NFS in the DEC hosts work fine, while was 
 really slow between Hp and DEC. For example the bdf HPUX
 command produce a slow output (also Hp to Hp).
 Ping command between DEC host was OK!!!, while produce 30-40% of loose 
 packets between HP to HP or HP to DEC.  
 
 I discovered that the problem was produced only when the two thinwire 
 segments are connected to DECREPEATER 90C (DECMR).

 I solved the problem using one DEMPR thinwire repeater like this 
 configuration:




            ---------
            |       |
            |DEMPR  |
         [L]|       |Port 1
Loopback on |       |------------------------------------------------------
 Tranceiv.  |       |							  |
    port    |       |Port 2						  |
            |       |---------------------------------------------------| | 
            |       |---------						| |
            ---------Port 3   |		      				| |
			      |						| |
			      |						| |
			      |						| |
		--------------|						| |
		|							| |
     DEChub 90	|	  F.O. TO BACKBONE				| |
   	----------------     /						| |
	| 		|   /						| |
	| Power supply  |  /						| |
	----------------- /  --------   --------  --------  ---------   | |
	| Slot 8 DEWGB	|/  |DEC5240 | |DEC5133 ||DEC5133 || DEC5133 |  | |
	-----------------    ________ 	________  ________  _________	| |
	| Slot 7 DECMR  |	|          |          |         |       | |
	| 	   	|    [T]----------------------------------------- |
	|		|       -------------------------------------------
	-----------------	|    -------	  
	| Slot 6 empty  |	|---| HP710 |HPUX A.08.07 A
	-----------------	|    -------
	| Slot 5 empty	|	|
	-----------------	|    ------
	| Slot 4 DSRVG	|	|---| HP720| HPUX A.B8.05 A
	-----------------	|    ------
	| Slot 3 DSRVG	|	|
	-----------------	|
	| Slot 2 DSRVG	|	|    ------------	
	-----------------	|---| HP9000/345 | HPUX 7.05 B
	| Slot 1 DSRVG	|	|    ------------
	----------------- 	|
				|
				|    ------------
				|---| HP9000/345 | HPUX 7.05 B
				|    ------------
				|
				|
				|    ------------
				|---| HP9000/360 | HPUX 7.05 B
				|    ------------
				|
				|
				|
				|   -----------	
				|   |         |
				|---|APOLLO   | [PRIVATE APOLLO NETWORK]
				|   |	WSTAT.|-----------------------   
				|   |---------	
			       [T]	


- DECbridge's display utility, showed no error on Work group and backbone
  side (Unsent, excessive collisions: 0 - Unsent, carrier check failed: 0 -
  Unsent, lifetime exceeded: 0 - Received block check error : 0 - Received
  framing error: 0 .......less then 10% of collision compared to frames 
  sent)
- Show port command, verified no segmentation on repeater ports.
- Lan segment utilization was normal, from 1 to 7 % ( Spider tool ).
- No error conditions are visible from DATALINK COUNTER (netstat -I lno -s)
  in the DEC hosts.
- The unused thinwire ports have terminator on DECRepeater90-C.
- After found workaround, the customer doesn't permit to us, analyze the 
  problem during work time on the original network configuration.
- By the way, i can't reproduce the problem after work time with
  ping command on the original network configuration.
- If i connect the Hp and DEC host on the same thinwire segment, EVERYTHING 
  work fine (!!!!!).

	QUESTIONS:
--------------------------

- Any body have seen similar trouble on HP machine connect via DECrepeater 
  90C?
- Any feedback about the workaround is appreciated. Is it a supported 
  configuration?
- Some suggestion on troubleshooting the problem?
- What are the operating difference between DEMPR and DECMR?

  MANY THANKS 
  ===========

  Loris Span & Andrea Mattioli (SSU Padova - Italy)