[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
