Cabletron Systems MT8-MIM Spezifikationen PDF herunterladen (Seite 34)

Chapter 3: Booting/Image Code Loading Problems

3-16 Troubleshooting Guide

Download Requirements:

The ﬁle transfer from a UNIX station to the device is done by using TFTP (Trivial File Transfer Protocol),

which is connectionless. This can be initiated on a device from a Network Management System. If that device

will not accept a TFTP download, then BootP (Bootstrap Protocol) is used.

Before a device requests a download, it needs to know three parameters:

• IP address of itself

• IP address of download server

• Filename of ﬁrmware image

TFTP Preparations:

TFTP assumes the device has been told the three pieces of information already via SNMP sets or a Network

Management System. However, the /etc/inetd.conf conﬁguration ﬁle must have tftpd set up and initialized with

the conﬁguration.

Cabletron Systems Device Requirements:

1. You must have Super-User access to the device to initiate a download. (Some Cabletron Systems devices

only require Read-Write. Don’t spend time guessing, just use Super-User privileges.)

2. Users must have read permissions to Download file (permissions that never fail: % chmod 777 filename).

3. The Cabletron Systems device must have its own IP address in boot portion of NVRAM (not to be confused

with the IP address that is assigned and kept in the Local Management (LM) portion of NVRAM). Once the

download is initiated, the Cabletron Systems device does a Reverse Address Resolution Protocol (RARP)

request to itself with its IP Address. (Not all devices support this feature.)

4. Cabletron Systems device must have the MAC address for the TFTP download servers. Once the download

is initiated, the Cabletron Systems device does an ARP request to the server and waits for a response. The

device times out after 3 tries.

The following shows the sequence of events when you click the system reboot or start download button on

the management screen:

• Set requests get set at the device.

• The device reboots.

• The device RARPs itself. (I’ve got my MAC, do I have my IP?) Look for the device ip addr in the

packet.

• The device ARPs the server. (Hey there server, I’ve got your ip, what’s your MAC?) Look for the

server to respond with its MAC.

• The device does a TFTP READ REQUEST. (Device asks the server. Can I read the ﬁle?)

• The device and server begin transferring data: tftp read followed by tftp ack.

TIP: Set up an analyzer and watch the action! Any of the requirements above could result in

failure. Requirements 3 and 4 are points of failure that can only be veriﬁed with an analyzer. To

see the RARP and ARP requests, you must use a ﬁlter on the MAC address (Data Link layer)

(try using a bilateral on the MAC address of the device). You will not see these requests at the

IP layer.

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Cabletron Systems MT8-MIM Spezifikationen Seite 34