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Posted: Mon Nov 05, 2007 12:24 pm Post subject: Determine the device is a router or switch given the Device |
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I Have a Linksys Managed Switch and a Cisco router
Using SNMP protocol I am trying determine the device is a router or
switch and
Also which all layers are supported by the device?
Following methods are used .
Issue a get request for: "sysObjectId", "sysDescr", "sysServices",
"ipForwarding".
Here is my problem I am surprised by the output of "sysServices"
For Cisco router sysServices = 78
For Cisco router ipForwarding = 1
For Linksys switch sysServices = 2
For Linksys switch ipForwarding = 2
For For windows workstation sysServices = 76
My Linksys Switch is a Layer 2 Device
Then value Should be 3 = 2^ (1-1) + 2 ^(2-1)
For Computing sysServices value blow stated Equation is used
Note:
A value which indicates the set of services that this
entity may potentially offer. The value is a sum.
This sum initially takes the value zero. Then, for
each layer, L, in the range 1 through 7, that this node
performs transactions for, 2 raised to (L - 1) is added
to the sum. For example, a node which performs only
routing functions would have a value of 4 (2^(3-1)).
In contrast, a node which is a host offering application
services would have a value of 72 (2^(4-1) + 2^(7-1)).
Note that in the context of the Internet suite of
protocols, values should be calculated accordingly:
layer functionality
1 physical (e.g., repeaters)
2 datalink/subnetwork (e.g., bridges)
3 internet (e.g., supports the IP)
4 end-to-end (e.g., supports the TCP)
7 applications (e.g., supports the SMTP)
For systems including OSI protocols, layers 5 and 6
may also be counted.
1.What are Possible values for sysServices ?
How the sysServices value computed by the vendors?
Thanks in advance |
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