The Routing Over Large Clouds Mailing List Archive by date[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] CSR
It seems to me that some ion members don't understand a CSR
correctly.
The CSR is a router with cell-swithing fabric.
It can forward IP packets and can also forward data cell by cell.
host CSR(Cell-Switching Router) host
+----+ +-----------------------------+ +----+
| | ATM switch | IP packet forwarding fabric | ATM switch | |
| | +----+ +-----------------------------+ +----+ | |
| |----| |----| cell switching fabric |----| |----| |
+----+ +----+ +-----------------------------+ +----+ +----+
an IP subnet | another IP subnet
<--------------- | ----------------->
The CSR usally forwars IP packets as a conventional router.
But it forwards data cell by cell without packetization,
when it recognizes that a VC is only used for data transmision
from/to a VC in another IP subnet.
Such recognization is carreid out by the RSVP or something.
(The only problem is that TTLs can not be discreased.)
There exist, of course, no CSRs as commercial products.
But you can implement them by combining a workstation
with a PVC/SVC ATM switch.
The easiest implementation is as the following:
workstation
+---------------+
| gated |
+-------+-------+
|ATM NIC|ATM NIC|
+-------+-------+
| |
+---------------+
--------| |---------
+---------------+
ATM switch
The workstation controls the ATM swtich by a PVC interface
via RS-232c.
Data transmission without QoS is:
workstation
+---------------+
| +-------+ |
+---|---+---|---+
| | | | |
+---|---+---|---+
| |
+---|-------|---+
<-----------+ +------------>
+---------------+
ATM switch
Data transmission with QoS is:
workstation
+---------------+
| gated |
+-------+-------+
|ATM NIC|ATM NIC|
+-------+-------+
| |
+---------------+
<-------------------------------->
+---------------+
ATM switch
Is the CSR so odd?
----------------------------------------------------------
FUJIKAWA, Kenji @ Dept. of Info. Sci., Kyoto Univ., Japan
TEL +81 75-753-5387 FAX +81 75-751-0482
e-mail magician@kuis.kyoto-u.ac.jp
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