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Conference netcad::hub_mgnt

Title:	DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:	Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:	NETCAD::COLELLADT

Created:	Wed Nov 13 1991
Last Modified:	Fri Jun 06 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	4455
Total number of notes:	16761

2333.0. "Throughput of DECrepeater 900" by HGOVC::WILLIAMNG () Thu Jun 01 1995 05:54

    Hello there, I'm a system support for Hong Kong Digital office.  We
    bought a DEChub 900, a DEChub 90, a DECswith 900 and a DECrepeater 900. 
    I have questions about the throughput of these network equipment.
    
    1)  A DECrepeater 900 has 32 UTP ports.  Is the throughput of the whole
    DECrepeater 10mbs or each individual port 10mbs ?  I personally don't
    believe it is later.  But if the whole DECrepeater has a throughtput of
    10mb, then I'll get a very slow response if I connect 32 "system" to
    this repeater because each will only get 10/32 throughput ?
    
    2)	Is the throughput of a repeater 90 different from a repeater 900 ?
    
    I'm not a network expert so these questions may not be "sound".  Please
    correct me if I'm wrong in concept.  Also, I need to set up filtering
    on the DECswitch 900.  Can anyone give me a pointer for relevent
    documents ? I need to setup address filter, not protocol filtering.
    
    William

T.R	Title	User	Personal Name	Date	Lines
2333.1	See notes 895 & 1879 for info on DECswitch 900 filtering	NETCAD::BATTERSBY		`Thu Jun 01 1995 13:36`	7
	On relevant info on filtering, check the following notes and their follow-on replies. These may help answer your questions on filtering on the DECswitch 900 you have. notes #895 & #1879 Bob
2333.2	Throughput.	NETCAD::GALLAGHER		`Thu Jun 01 1995 14:01`	35
	Hello, > 1) A DECrepeater 900 has 32 UTP ports. Is the throughput of the whole > DECrepeater 10mbs or each individual port 10mbs ? I personally don't > believe it is later. This question could start some very academic discussions. I'll give it a shot anyway. The capacity of an Ethernet repeater is the sum of Ethernets on which it connects. It does not depend on the number of ports. As you no doubt know, Ethernet is a shared media. Per port switching repeaters can currently connect to up to 6 Ethernet segments. (This is a limitation of the repeater hardware, not a limitation of the hub backplane.) Therefore, when connected to 6 different Ethernets the capacity is 10Mb times 6 or 60Mb. If you believe the throughput of Ethernet to be 10Mb/s then the throughput is 60Mb/s. If you believe the reasonable throughput of Ethernet is 6.25 Mb/s then the throughput is 6 * 6.25 Mb/s. If all the ports are connected to one Ethernet then the throughput can be as high as 10Mb/s. > But if the whole DECrepeater has a throughput of > 10mb, then I'll get a very slow response if I connect 32 "system" to > this repeater because each will only get 10/32 throughput ? Calling a repeater a "PORTswitch" sometimes leads people to think of it as a bridge rather than a repeater. PORTswitching means that you can move ports to backplane LANs. This is very different from packet switching (bridging). So it doesn't matter how you group the repeater's ports. What matters is how many LANs you connect them to. -Shawn
2333.3	Not so simple	NETCAD::HERTZBERG	History: Love it or Leave it!	`Thu Jun 01 1995 14:22`	15
	>> But if the whole DECrepeater has a throughtput of 10mb, then I'll >> get a very slow response if I connect 32 "system" to this repeater >> because each will only get 10/32 throughput? This statement is an oversimplification. If all 32 systems are constantly demanding network bandwidth, then each may see something like 300kb/s throughput, as you state. But this is not a typical situation. If the network is relatively idle, and one of the stations decides it needs a large file transfer, that station may in fact see something near 10mb/s throughput. It all depends on what data transfer requirements the systems are making on their network connections. It is entirely possible that the response as perceived by the users will be perfectly adequate.