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Webcast-Catalyst9k
New Member

c3550 switch

Hello,

I have a Cisco C3550 switch that I am experiencing some issues with. The issues relates to PXE boot (the pre-boot environment for tasks like imaging).

This switch by default has the access ports configured to:

switchport mode dynamic desirable

spanning-tree portfast

This config is apparently for trunking and was hindering the PXE boot for the clients. The clients would not grab an IP address and boot file from the network. So I made some changes to the interface config as so:

switchport mode access

spanning-tree portfast

This config sort of resolved the issue, but not completely. The clients can now pick an IP address and boot file form the network, but the boot file does not load.

The interesting thing is if I connect the client/s to a c3500-XL switch, there are no problems. Clients get an IP address, boot file, and the boot file gets completely loaded. Life is good!

I have only encountered this issue with the c3550 switch. What is the necessary config on the switch's interfaces that will allowed the clients to boot properly and load the boot file? The clients, PXE Server, and DHCP server are all on the same subnet.

Why does it work on the c3500-XL switch and not on the c3550 switch?

The interface on the 3500-XL switch is configured like so:

spanning-tree portfast

Thanks in advance,

Carlos

5 REPLIES
Cisco Employee

Re: c3550 switch

Hi Carlos,

Can you try hardsetting speed and duplex settings on switch and client? I believe your clients are in vlan 1?

Regards,

Ankur

New Member

Re: c3550 switch

Setting the link settings seem not to be an option for me. Yes the clients are all in vlan 1. Are there any other options?

Thanks again,

Carlos

Re: c3550 switch

Carlos,

Can you post the output of 'show int (int#) switchport from both 3500-XL and c3550. Let's see if there's any difference in default port settings.

HTH

Sundar

New Member

Re: c3550 switch

I connected the workstation to both ports, one at a time, and grab the interface status.

"sh int" on c3500-XL:

cavec_dsu_idf600_s1#sh int fa0/11

FastEthernet0/11 is up, line protocol is up

Hardware is Fast Ethernet, address is 0006.53cc.740b (bia 0006.53cc.740b)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Auto-duplex (Full), Auto Speed (100), 100BaseTX/FX

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 1000 bits/sec, 2 packets/sec

1101001 packets input, 71913811 bytes

Received 359 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 196 multicast

0 input packets with dribble condition detected

2799751 packets output, 3669516334 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier

0 output buffer failures, 0 output buffers swapped out

"show int" on c3550:

cavec_dsu_idf600_s2#sh int fa0/1

FastEthernet0/1 is up, line protocol is up (connected)

Hardware is Fast Ethernet, address is 0012.437c.e181 (bia 0012.437c.e181)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 100Mb/s, media type is 10/100BaseTX

input flow-control is off, output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 1000 bits/sec, 1 packets/sec

11370 packets input, 1075448 bytes, 0 no buffer

Received 104 broadcasts (0 multicasts)

0 runts, 0 giants, 0 throttles

1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 23 multicast, 0 pause input

0 input packets with dribble condition detected

50606 packets output, 26127392 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 babbles, 0 late collision, 0 deferred

0 lost carrier, 0 no carrier, 0 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Thanks again,

Carlos

New Member

Re: c3550 switch

I wanted to add that I hardcoded the interface to 100Full. That solved my PXE boot issue. Although, I am afraid that it will cause more problems than it will solve. Because all my devices (at least clients) are at autonegotiate.

Thanks,

Carlos

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