[snip]
If you were to compare either of these
products to our notion of Switching and Routing in the IP/Ethernet world, these
are neither Switches or Routers....but simple Bridges, much like the early
Ethernet Bridges.
Camden,
Given that iSCSI is defined above TCP it falls in layer
5 . FCP on FC also does a similar function. From the networking protocol
perspective It may be better to call the ¡¥cisco Storage router¡¦ a SCSI gateway than a simple bridge.
Naveen nimmu
iSCSI switches are simple Ethernet
Switches or any other switch that can switch or route TCP/IP. Because
iSCSI utilizes TCP/IP, the iSCSI protocol rides as a byte stream on top of
TCP. Therefore, most switches are unaware that the packets that they are
switching or routing are actually iSCSI. They simply appear as another
TCP byte stream. So if you think in terms of Layer X switching, a simple
Layer 2 switch is a switch based in a transports like EThernet, a Layer 3
switch is a simple version of a router with IP forwarding inmplemented in
HW. A Layer 4 switch can prioritize traffic based on TCP
connections. In order to provide intelligence in a switch that recognizes
iSCSI, it would be somewhere in Layer 5-7 depending on what you filter on.
I would imaging that in order for any
product to be a Storage Router, there would have to be the notion of Global
Addressing of storage elements....something which does not exist today.
Technically, FC switching is based on
logical addressing, and not physical addresses, so it is most similar to Layer
3 switching in IP/EThernet....which some might call a router.
Camden ford
-----Original Message-----
From: Nike Chen
[mailto:nikechen@ksts.seed.net.tw]
Sent: Tuesday, January 15, 2002
12:29 AM
To: ips@ece.cmu.edu
Subject: Differences between iSCSI
Router (ex. CISCO RN5420) and iSCSI Switch (ex. SANRAD Switch 3000)
Hi All:
Would anybody tell me the function
differences between iSCSI Router and Switch,
or just like performance difference in
Layer 3 switch and Router?
When it say it is a iSCSI switch, what
level do it operate, level 2, 3 or 4?
When it say it is a iSCSI Router, what
level do it operate, or just a protocol
converting gateway?
Is there any definition for iSCSI Router or iSCSI switch?
Thanks,
Nike
