CCIE - 3920 Switch Dumb Question

Author

3920 Switch Dumb Question

doctorcisco

2002-04-30, 10:14 am

Yes, I got one of these beasties. Don't ask me why, but it's the switch system board and ports mounted on a piece of cardboard. It's uglier than ugly, but it powers up fine, console port works fine, etc. etc. Just no case around it. It sits on top of a Cat 1924 ethernet switch in my rack.

However, I'm having a problem that probably reveals my ignorance of token ring or a bit of overoptimism about cardboard-mounted system boards ...

After resetting the switch to factory default, I attached two routers (a 7000 and a 2504, as if that should matter). Both see the switch as a CDP neighbor, and the switch sees both routers. (Interestingly, I set the switch's hostname to trsw, but in the sh cdp neigh display on the routers, the hostname shows trsw with a bunch of digits after it ... some CDP anomaly?) Both router interfaces show up and happy, and increment frames in and out (the token and CDP traffic, presumably) with no errors. Both router interfaces work fine when cabled to a MAU. (Obviously, I have two different sets of cabling, since MAU's don't use RJ45). Both switch ports go green. With all that being true, I've tentatively ruled out media filter, cable, and other hardware issues. Since CDP works, we appear to be fine on layers 1-2.

However, neither router can ping the other. From what (little) I've read, this switch defaults to transparent bridging on all ports -- in other words, shouldn't the routers be able to ping one another? I really don't want to dive into this switch and all that token ring bridging material yet, I just want the switch to pretend it's a MAU for now.

What simple, dumb thing am I missing?

doc

MadChef

2002-04-30, 10:23 am

It sounds like you've got it all about right. You should probably go in and verify that your ports are in the same crf and linke to the same brf. You can always try to create new ones, put the ports in it and see if you can get L3 working. It's really a simple device. This is everything you need to know, really:
http://www.cisco.com/univercd/cc/td...0ug/vlantut.htm

MadChef

doctorcisco

2002-04-30, 11:18 am

Well, after swapping 1 router and some cables, and doing a reset on the switch again, and pasting a bunch of stuff into this message, I found my problem. It's dumb, all right. Since I already pasted all this junk, first one to find it gets to bonk me on the forehead.

Oh, wait, since I was the first one to find it ..... <BONK>

Sheepishly,
doc

7000-1#sh int to2/3
TokenRing2/3 is up, line protocol is up
Hardware is cxBus Token Ring, address is 0000.3090.4062 (bia 0000.3090.4062)
Internet address is 192.169.10.70/24
MTU 4464 bytes, BW 16000 Kbit, DLY 630 usec, rely 255/255, load 1/255
Encapsulation SNAP, loopback not set, keepalive set (10 sec)
ARP type: SNAP, ARP Timeout 04:00:00
Ring speed: 16 Mbps
Single ring node, Source Route Transparent Bridge capable
Group Address: 0x00000000, Functional Address: 0x08000000
Ethernet Transit OUI: 0x000000
Last input 00:00:02, output 00:00:02, output hang never
Last clearing of "show interface" counters 00:04:11
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 0 bits/sec, 0 packets/sec
37 packets input, 2562 bytes, 0 no buffer
Received 12 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
29 packets output, 2036 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 transitions

7000-1#sh cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
000577:1A9600 Tok 2/3 179 B S CAT3920 1/2

4500-1#sh int to0
TokenRing0 is up, line protocol is up
Hardware is TMS380, address is 0008.dec3.c452 (bia 0008.dec3.c452)
Internet address is 192.168.10.45/24
MTU 4464 bytes, BW 16000 Kbit, DLY 630 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation SNAP, loopback not set
Keepalive set (10 sec)
ARP type: SNAP, ARP Timeout 04:00:00
Ring speed: 16 Mbps
Duplex: half
Mode: Classic token ring station
Group Address: 0x00000000, Functional Address: 0x08000000
Ethernet Transit OUI: 0x000000
Last input 00:00:03, output 00:00:03, output hang never
Last clearing of "show interface" counters 00:14:20
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 0 bits/sec, 0 packets/sec
339 packets input, 14886 bytes, 0 no buffer
Received 266 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
108 packets output, 11562 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 transitions

4500-1#sh cdp neigh
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater

Device ID Local Intrfce Holdtme Capability Platform Port ID
000577:1A9600 Tok 0 160 B S CAT3920 1/3

Display VTP VLAN Configuration Menu
VTP VLAN Configuration

TrBRF/TrCRF ID Brdg/Rng Ports Local State
trbrf-default 1005 0x0F preferred
trcrf-default 1003 auto yes preferred

(These are the default BRF and CRF for the switch).

Display the Local VLAN Port Configuration Menu
Local VLAN Port Configuration

Port Mode TrCRF TrBRF
1 Static trcrf-default trbrf-default
2 Static trcrf-default trbrf-default
3 Static trcrf-default trbrf-default

Yankee

2002-05-01, 4:15 am

address typo? *BONK*

Yankee

MadChef

2002-05-01, 6:08 am

DOH!!!!! Doncha just hate that!

doctorcisco

2002-05-01, 11:32 am

quote:
Originally posted by MadChef
DOH!!!!! Doncha just hate that!

Yep ... another high-grade network issue SOLVED!!!!

doc

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