What is the proccess of "shutdown" command?

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Jul 8th, 2010
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Hello!


Here is a nube question:


refer to a scheme:


Router Eth0 <---------> Fa0/1 Switch


I enter "shutdown" command on Fa0/1 interface of a switch,after that i see from Router:


router#sh int ethernet 0

Ethernet0 is up, line protocol is down
<...>


The manual only says that the "shutdown" command switches off all functions on interface.

What is the physical basis of the processing of this command ?

As I see, it only switches off Layer2 protocol (802.3). Doesn't it turns off the TX/RX circuits on interface controller?


Thanks!

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gephelps Sun, 07/11/2010 - 10:56
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  • Cisco Employee,

If you look at the output of show interfaces on the switch does F0/1 show administratively down?


How is the interface configured on the router? If you look at the rest of the output for show interfaces on the router for Ethernet 0, is the interface listed as force up?

Alexander Demin Sun, 07/11/2010 - 22:48
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If you look at the output of show interfaces on the switch does F0/1 show administratively down?

The switch:


Switch#sh ip int br | i FastEthernet0/24
FastEthernet0/24       unassigned      YES unset  administratively down down


Switch#sh interfaces fastEthernet 0/24
FastEthernet0/24 is administratively down, line protocol is down (disabled)
  Hardware is Fast Ethernet, address is 000b.be70.c198 (bia 000b.be70.c198)
  Description: toAS
  MTU 1536 bytes, BW 10000 Kbit, DLY 1000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Carrier delay is 60 sec
  Auto-duplex, Auto-speed, 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 00:02:17, output 00:01:54, output hang never
  Last clearing of "show interface" counters 1y1w
  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 0 bits/sec, 0 packets/sec
     4070917 packets input, 409316490 bytes, 0 no buffer
     Received 537322 broadcasts (0 multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 537305 multicast, 0 pause input
     0 input packets with dribble condition detected
     24987835 packets output, 2083851785 bytes, 0 underruns
     0 output errors, 53 collisions, 15 interface resets
     0 babbles, 0 late collision, 859 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out


On Router:


Router#sh ip int br
Interface              IP-Address      OK? Method Status                Protocol
Ethernet0              192.168.1.2    YES NVRAM  up                    down


Router#sh interfaces ethernet 0
Ethernet0 is up, line protocol is down
  Hardware is Lance, address is 0010.7be8.6a30 (bia 0010.7be8.6a30)
  Internet address is 192.168.1.2/25
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 205/255, load 1/255
  Encapsulation ARPA, loopback not set, keepalive set (10 sec)
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:03:58, output 00:00:00, 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 0 bits/sec, 0 packets/sec
     154049 packets input, 21687338 bytes, 0 no buffer
     Received 138293 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 input packets with dribble condition detected
     123303 packets output, 11881586 bytes, 0 underruns
     517 output errors, 3 collisions, 5 interface resets
     0 babbles, 0 late collision, 39 deferred
     517 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out


How is the interface configured on the router?


Router#sh run interface ethernet 0
Building configuration...

Current configuration:
!
interface Ethernet0
ip address 192.168.1.2 255.255.255.128
no ip redirects
no ip directed-broadcast
no ip proxy-arp
end


The Router is: cisco AS2511-RJ, IOS: 2500 Software (C2500-I-L), Version 12.0(8b), RELEASE SOFTWARE (fc1)
The Switch is: Cisco WS-C3550-24, IOS: C3550 Software (C3550-I5Q3L2-M), Version 12.2(25)SEA, RELEASE SOFTWARE (fc)


P.S.:


I read this article: http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Ethernet.html#wp1020832

Here is what is said about 10Base-T:


10Base-T was also the first Ethernet version to include a link integrity  test to determine the health of the link. Immediately after powerup,  the PMA transmits a normal link pulse (NLP) to tell the NIC at the other  end of the link that this NIC wants to establish an active link  connection:

If the NIC at the other end of the link  is also powered up, it responds with its own NLP.

If the NIC at the other end of the link  is not powered up, this NIC continues sending an NLP about once every  16 ms until it receives a response.

The link is activated only after both NICs are capable of exchanging  valid NLPs.

  

PMA stands for Physical Media Attachment sublayer of a Physical OSI Layer. So  I wonder whether the "shutdown" command stops Layer 2 functionality or it also stops Layer 1 (PHY) and powers off the interface ?



Thanks!

perpignanetworking Mon, 07/12/2010 - 13:02
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well,


unless you physically disconnect the cable you´r not gonna see down down. This is quiet normal. Run a show controller and you will see the physical connection of the interface.


Cheers

Alexander Demin Tue, 07/13/2010 - 04:59
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unless you physically disconnect the cable you´r not gonna see down down. This is quiet normal. Run a show controller and you will see the physical connection of the interface.

Okay, here is the output before shutdown:

#sh controllers ethernet 0

LANCE unit 0, idb 0xBAFC8, ds 0xBC8D8, regaddr = 0x2130000, reset_mask 0x2
IB at 0x606E64: mode=0x0000, mcfilter 0000/0000/0100/0000
station address 0010.7be8.6a30  default station address 0010.7be8.6a30
buffer size 1524
RX ring with 16 entries at 0x606EA8
Rxhead = 0x606EC0 (3), Rxp = 0xBC900 (3)
00 pak=0x0BEFFC ds=0x60E9A2 status=0x80 max_size=1524 pak_size=96
01 pak=0x0BE5E8 ds=0x60C7F6 status=0x80 max_size=1524 pak_size=96
02 pak=0x0BF608 ds=0x60FDD6 status=0x80 max_size=1524 pak_size=96
03 pak=0x0C0424 ds=0x612CFA status=0x80 max_size=1524 pak_size=64
04 pak=0x0BDBD4 ds=0x60A64A status=0x80 max_size=1524 pak_size=64
05 pak=0x0BDFDC ds=0x60B3C2 status=0x80 max_size=1524 pak_size=64
06 pak=0x0BD9D0 ds=0x609F8E status=0x80 max_size=1524 pak_size=64
07 pak=0x0BE7EC ds=0x60CEB2 status=0x80 max_size=1524 pak_size=88
08 pak=0x0BF404 ds=0x60F71A status=0x80 max_size=1524 pak_size=64
09 pak=0x0C001C ds=0x611F82 status=0x80 max_size=1524 pak_size=64
10 pak=0x0BF80C ds=0x610492 status=0x80 max_size=1524 pak_size=64
11 pak=0x0BDDD8 ds=0x60AD06 status=0x80 max_size=1524 pak_size=64
12 pak=0x0BEDF8 ds=0x60E2E6 status=0x80 max_size=1524 pak_size=75
13 pak=0x0BFE18 ds=0x6118C6 status=0x80 max_size=1524 pak_size=64
14 pak=0x0BFC14 ds=0x61120A status=0x80 max_size=1524 pak_size=64
15 pak=0x0BF200 ds=0x60F05E status=0x80 max_size=1524 pak_size=254
TX ring with 4 entries at 0x606F68, tx_count = 0
tx_head = 0x606F80 (3), head_txp = 0xBC954 (3)
tx_tail = 0x606F80 (3), tail_txp = 0xBC954 (3)
00 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
01 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
02 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
03 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
0 missed datagrams, 0 overruns
0 transmitter underruns, 0 excessive collisions
2 single collisions, 1 multiple collisions
0 dma memory errors, 0 CRC errors


0 alignment errors, 0 runts, 0 giants
0 tdr, 0 spurious initialization done interrupts
0 no enp status, 0 buffer errors, 0 overflow errors
0 tx_buff, 0 throttled, 0 enabled
Lance csr0 = 0x73


and after shutdown:


#sh controllers ethernet 0

LANCE unit 0, idb 0xBAFC8, ds 0xBC8D8, regaddr = 0x2130000, reset_mask 0x2
IB at 0x606E64: mode=0x0000, mcfilter 0000/0000/0100/0000
station address 0010.7be8.6a30  default station address 0010.7be8.6a30
buffer size 1524
RX ring with 16 entries at 0x606EA8
Rxhead = 0x606ED0 (5), Rxp = 0xBC908 (5)
00 pak=0x0BF200 ds=0x60F05E status=0x80 max_size=1524 pak_size=64
01 pak=0x0BEFFC ds=0x60E9A2 status=0x80 max_size=1524 pak_size=64
02 pak=0x0BE5E8 ds=0x60C7F6 status=0x80 max_size=1524 pak_size=64
03 pak=0x0BF608 ds=0x60FDD6 status=0x80 max_size=1524 pak_size=75
04 pak=0x0BFC14 ds=0x61120A status=0x80 max_size=1524 pak_size=64
05 pak=0x0BDBD4 ds=0x60A64A status=0x80 max_size=1524 pak_size=75
06 pak=0x0C0A30 ds=0x61412E status=0x80 max_size=1524 pak_size=64
07 pak=0x0BD9D0 ds=0x609F8E status=0x80 max_size=1524 pak_size=64
08 pak=0x0BE7EC ds=0x60CEB2 status=0x80 max_size=1524 pak_size=130
09 pak=0x0BF404 ds=0x60F71A status=0x80 max_size=1524 pak_size=399
10 pak=0x0BDFDC ds=0x60B3C2 status=0x80 max_size=1524 pak_size=307
11 pak=0x0BF80C ds=0x610492 status=0x80 max_size=1524 pak_size=254
12 pak=0x0BDDD8 ds=0x60AD06 status=0x80 max_size=1524 pak_size=64
13 pak=0x0BEDF8 ds=0x60E2E6 status=0x80 max_size=1524 pak_size=64
14 pak=0x0BFE18 ds=0x6118C6 status=0x80 max_size=1524 pak_size=75
15 pak=0x0C001C ds=0x611F82 status=0x80 max_size=1524 pak_size=64
TX ring with 4 entries at 0x606F68, tx_count = 0
tx_head = 0x606F68 (0), head_txp = 0xBC948 (0)
tx_tail = 0x606F68 (0), tail_txp = 0xBC948 (0)
00 pak=0x000000 ds=0x63162E status=0x03 status2=0x0000 pak_size=182
01 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
02 pak=0x000000 ds=0x62366A status=0x03 status2=0x0000 pak_size=60
03 pak=0x000000 ds=0x631626 status=0x03 status2=0x0000 pak_size=60
0 missed datagrams, 0 overruns
0 transmitter underruns, 0 excessive collisions
2 single collisions, 1 multiple collisions
0 dma memory errors, 0 CRC errors


0 alignment errors, 0 runts, 0 giants
0 tdr, 0 spurious initialization done interrupts
0 no enp status, 0 buffer errors, 0 overflow errors
0 tx_buff, 0 throttled, 0 enabled
Lance csr0 = 0x4


Unfortunately, I do not see much difference.


Thanks

perpignanetworking Tue, 07/13/2010 - 06:04
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26051980DAO escribió:


Hello!


Here is a nube question:


refer to a scheme:


Router Eth0 <---------> Fa0/1 Switch


I enter "shutdown" command on Fa0/1 interface of a switch,after that i see from Router:


router#sh int ethernet 0

Ethernet0 is up, line protocol is down
<...>


The manual only says that the "shutdown" command switches off all functions on interface.

What is the physical basis of the processing of this command ?

As I see, it only switches off Layer2 protocol (802.3). Doesn't it turns off the TX/RX circuits on interface controller?


Thanks!


TX/RX is layer 1, up down means interface is up protocol is down. Put no shutdown in the switch interface and you will see up up in the router.

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