D-H,appy

vlan
=================
1. conf)#vlan 10

2. #vlan database
  -vlan)#vlan 10
=================
interface fa0/1
 switchport mode access
 swtichport access vlan 10
=================
확인
 show vlan
 show vlan-switch
=================

trunk
=================
 1. 802.1Q (TAG) IEEE
 2. ISL (Encapsulation) CISCO
=================
interface fa0/1
 switchport trunk encapsulation [dot1q, isl]
 switchport mode trunk
=================
확인
 show interface trunk
=================
(DTP,Native vlan(802.1Q), allowed vlan)

switchport mode access
switchport mode trunk (DTP)
switchport mode dynamic desirable (DTP)
switchport mode dynamic auto (Default)

-------------------------------------------
2일차

VTP (VLAN TRUNK PROTOCOL) CISCO
1. trunk
2. VTP domain name
3. (option)vtp password
==================
1. config)#vtp domain BCMSN
   config)#vtp mode [server, client, transparent]
   config)#vtp pruning ===> no vtp pruning
   cnofig)#vtp password cisco ===> no vtp password

2. #vlan database
   -vlan)#vtp domain BCMSN
   -vlan)#vtp [server, client, transparent]
   -vlan)#vtp pruning
   -vlan)#vtp password cisco
==================
확인
show vtp status
show vtp counters
==================

------------------------------------------
실습2

sw1(config)#interface fa1/1
sw1(config-if)#switchport mode trunk
sw1(config-if)#no shut
sw1(config-if)#exit
sw1(config)#interface fa1/3
sw1(config-if)#switchport mode trunk
sw1(config-if)#no shut
sw1(config-if)#exit

sw2(config)#interface fa1/1
sw2(config-if)#switchport mode trunk
sw2(config-if)#no shut
sw2(config-if)#exit
sw2(config)#interface fa1/5
sw2(config-if)#switchport mode trunk
sw2(config-if)#no shut
sw2(config-if)#exit

sw3(config)#interface fa1/5
sw3(config-if)#switchport mode trunk
sw3(config-if)#no shut
sw3(config-if)#exit
sw3(config)#interface fa1/3
sw3(config-if)#switchport mode trunk
sw3(config-if)#no shut
sw3(config-if)#exit
---------
확인
show interface trunk

sw1(config)#interface vlan 1
sw1(config-if)#ip address 192.168.1.1 255.255.255.0
sw1(config-if)#no shut

sw2(config)#interface vlan 1
sw2(config-if)#ip address 192.168.1.2 255.255.255.0
sw2(config-if)#no shut

sw3(config)#interface vlan 1
sw3(config-if)#ip address 192.168.1.3 255.255.255.0
sw3(config-if)#no shut
--------

sw1#vlan database
sw1(vlan)#vtp domain BCMSN
Domain name already set to BCMSN .
sw1(vlan)#vtp server
Device mode already VTP SERVER.
sw1(vlan)#

sw2#vlan database
sw2(vlan)#vtp domain BCMSN
Domain name already set to BCMSN .
sw2(vlan)#vtp client
Setting device to VTP CLIENT mode.
% not enough space on flash to store vlan database. trying squeeze...First create squeeze log by erasing the entire device

% error squeezing flash - (Missing or corrupted log)
sw2(vlan)#

sw3#vlan database
sw3(vlan)#vtp domain BCMSN
Domain name already set to BCMSN .
sw3(vlan)#vtp client
Setting device to VTP CLIENT mode.
% not enough space on flash to store vlan database. trying squeeze...First create squeeze log by erasing the entire device

% error squeezing flash - (Missing or corrupted log)
sw3(vlan)#

-------
vlan 생성

sw1#vlan database
sw1(vlan)#vlan 10
VLAN 10 modified:
sw1(vlan)#vlan 20
VLAN 20 modified:
sw1(vlan)#vlan 30
VLAN 30 modified:
sw1(vlan)#vlan 40
VLAN 40 modified:
sw1(vlan)#vlan 50
VLAN 50 modified:
sw1(vlan)#vlan 60
VLAN 60 modified:
--------
2,3번에서 vlan 생성 확인
show vlan-switch
show vtp status

--------
sw2, sw3에서는 vlan 생성 안됨

--------

sw1#vlan database
sw1(vlan)#vtp password cisco
Setting device VLAN database password to cisco.
sw1(vlan)#vlan 10
VLAN 10 added:
    Name: VLAN0010
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#

암호때문에 sw2,sw3 vlan 10 생성 X

sw2#vlan database
sw2(vlan)#vtp password cisco
Setting device VLAN database password to cisco.
sw2(vlan)#exit
In CLIENT state, no apply attempted.
Exiting....
sw2#

sw3#vlan database
sw3(vlan)#vtp password cisco
Setting device VLAN database password to cisco.
sw3(vlan)#exit
In CLIENT state, no apply attempted.
Exiting....

sw1#vlan database
sw1(vlan)#vlan 70
VLAN 70 added:
    Name: VLAN0070
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#

확인하면 이제 생성 O

----------------
transparent mode

sw2#  vlan database
sw2(vlan)#vtp transparent   ==>> revision num 0
Setting device to VTP TRANSPARENT mode.
sw2(vlan)#exit
APPLY completed.
Exiting....

sw2#show vtp status
VTP Version                     : 2
Configuration Revision          : 0
Maximum VLANs supported locally : 256
Number of existing VLANs        : 12
VTP Operating Mode              : Transparent
VTP Domain Name                 : BCMSN
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0xB9 0x0D 0xD8 0x07 0x70 0x8D 0xF7 0x88
Configuration last modified by 192.168.1.1 at 3-1-93 00:11:15

sw1(vlan)#vlan 80
VLAN 80 added:
    Name: VLAN0080

--> sw3에만 80 생성

--------------
pruning

sw1#vlan database
sw1(vlan)#vtp pruning
Pruning switched ON
sw1(vlan)#exit
APPLY completed.
Exiting....
sw1#

VTP Pruning Mode                : Enabled

----------------------------------------------
교재 5장.

native vlan (untag traffic) ===> vlan 1 (default) ===> vlan X
VLAN 1 ===> management traffic

----------------------------------------------
교재 6장.

STP(Spanning-tree protocol) 802.1D PVST
 IEEE표준
 1. 시간 - 해결 : RSTP(Rapid Spannnig-tree protocol) 802.1W
 2. CPU  - 해결 : MSTP(Multiple Spanning-tree protool) 802.1S
 
 CISCO표준
 1. 시간 - portfast, unlinkfast, backbonfast

----------------
실습2-5번문제

show spanning-tree vlan 1 brief

sw3#show spanning-tree vlan 1 brief

VLAN1
  Spanning tree enabled protocol ieee
  Root ID    Priority    32768
             Address     c800.0c58.0000
             Cost        19
             Port        44 (FastEthernet1/3)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     c802.0c58.0000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/3      128.44   128    19 FWD     0 32768 c800.0c58.0000 128.44
FastEthernet1/5      128.46   128    19 BLK    19 32768 c801.0c58.0000 128.46

--------------------------
port status

1. listen (STP) ==> loop방지 (15sec)
2. learn (MAC 학습) ==> broadcast 감소 (15sec)
3. forwarding

------------------

==STP 계산법==
1. Root bridge 선출 (VLAN 마다)
   (Priority(32768) ==> MAC) 낮은값 우선

2. Root port 선출 (non-root bridge마다)
   (cost ==> port-id(sender port-id, 자신의 포트 아이디가 아니라 상대방의 포트 아이디)) 낮은값 우선
   (100M ==> 19, 10M ==> 100)
  
3. Designated port선출 (segment 마다)
   (cost

sw3#show spanning-tree vlan 1 brief
로 확인

-----------------

port role
1. designated port (BPDU 송신)
2. root port       (BPDU 수신)
3. blocking port   (BPDU 수신) traffic 차단

Root bridge 조정 (SW1 ROOT Bridge ===> SW3)
 sw3
  config)#spanning-tree vlan 1 priority 32767
 
  config)#spanning-tree vlan 1 root primary
  config)#spanning-tree vlan 1 root secondary

결과
sw2#show spanning-tree vlan 1 brief
FastEthernet1/1      128.42   128    19 BLK    19 32768 c800.0c58.0000 128.42
blocking 되어있음

------------------

 sw2
  spanning-tree vlan 1 root primary

결과
sw1 > FastEthernet1/3      128.44   128    19 BLK    19 32767 c802.0c58.0000 128.44

------------------

BPDU 의 타입 두가지
 1. configuration BPDU
 2. TCN BPDU
 

# IEEE 802.1d STP 포트 상태

1) Blocking (BLK)

 - 브릿징 루프를 해결하기 위해서 프레임 송수신이 불가능한 포트 차단 상태
 - BPDU만 수신 가능
 - BPDU 송신 불가능
 - 프레임 송수신 불가능
 - Max Age Time : 20초

2) Listening (LIS)

 - Blocking 다음 단계에 시작하거나, 사용하지 않는 포트에 노드가 연결될 경우 시작
 - 루프 체크 단계
 - BPDU만 수신 가능
 - BPDU 송신 불가능
 - 프레임 송수신 불가능
 - Forward Delay Time : 15초

3) Learning (LRN)

 - Mac 주소 학습 단계
 - BPDU 송수신 가능
 - 프레임 송수신 불가능
 - Forward Delay Time : 15초

4) Forwarding (FWD)

 - 프레임 송수신 가능 상태
 - BPDU 송수신 가능

[참고] Portfast

 - 스위치 포트에 PC/라우터(플러딩이 실시되지 않는 장비)를 연결할 경우
    Listening 단계가 불필요하기 때문에 Portfast 기능을 사용하면 바로 Forwarding으로
    이전하게 된다.

 - Portfast 설정된 스위치 포트에 스위치/허브(플러딩 장비)가 연결될 경우
   Listening 단계가 삭제되었기 때문에 브릿징 루프가 발생될 수 있다.

Ex) Portfast 이전 디버깅

SW1[Fa1/9] <----------- [Fa0/0]R3

SW1#debug spanning-tree events
Spanning Tree event debugging is on

SW1(config)#int fa1/9
SW1(config-if)#no shutdown
SW1(config-if)#
*Mar  1 00:07:50.039: STP: VLAN1 Fa1/9 -> listening

*Mar  1 00:08:05.039: STP: VLAN1 Fa1/9 -> learning

*Mar  1 00:08:20.039: STP: VLAN1 Fa1/9 -> forwarding

Ex) Portfast 설정 이후 디버깅

SW1(config-if)#spanning-tree portfast
%Warning: portfast should only be enabled on ports connected to a single host.
 Connecting hubs, concentrators, switches,  bridges, etc.to this interface
 when portfast is enabled, can cause temporary spanning tree loops.
 Use with CAUTION

%Portfast has been configured on FastEthernet1/9 but will only
 have effect when the interface is in a non-trunking mode.
SW1(config-if)#switchport mode access

SW1(config-if)#no shut

*Mar  1 00:09:17.639: STP: VLAN1 Fa1/9 ->jump to forwarding from blocking

# PVST (Per VLAN Spanning-Tree)

 - VLAN 당 STP를 제공하는 서비스

vlan 11 <- STP
vlan 12 <- STP
vlan 13 <- STP
vlan 14 <- STP

 - 스위치에서 PVST 서비스를 이용하여 VLAN 로드 분산이 가능하다.

SW2(config)# spanning-tree vlan 11 priority 4096
SW3(config)# spanning-tree vlan 11 priority 16384

SW3(config)# spanning-tree vlan 12 priority 4096
SW2(config)# spanning-tree vlan 12 priority 16384

SW1# show spanning-tree vlan 11 brief <- SW1 Fa1/15 BLK
SW1# show spanning-tree vlan 12 brief <- SW1 Fa1/10 BLK

SW1#show spanning-tree vlan 11 brief

VLAN11
  Spanning tree enabled protocol ieee
  Root ID    Priority    4096
             Address     c401.01e0.0001
             Cost        19
             Port        51 (FastEthernet1/10)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     c400.01e0.0001
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/10     128.51   128    19 FWD     0  4096 c401.01e0.0001 128.52
FastEthernet1/15     128.56   128    19 BLK    19 16384 c402.01e0.0001 128.55

SW1#show spanning-tree vlan 12 brief

VLAN12
  Spanning tree enabled protocol ieee
  Root ID    Priority    4096
             Address     c402.01e0.0002
             Cost        19
             Port        56 (FastEthernet1/15)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     c400.01e0.0002
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/10     128.51   128    19 BLK    19 16384 c401.01e0.0002 128.52
FastEthernet1/15     128.56   128    19 FWD     0  4096 c402.01e0.0002 128.55

# VTP(VLAN Trunk Protocol)

 - Cisco에서 개발한 프로토콜, Cisco 장비에서만 동작 가능하다.
 - VTP란 트렁크로 구성된 환경에서 스위치간에 VLAN 정보를 공유(Share)하는 기능
 - 단, VLAN 생성/삭제/수정에 대한 정보만 공유하며, 포트를 Access한 내용을 공유 X

 - VTP 사용 조건

 1) 트렁크 구간(Access X)
 2) VTP 도메인 일치
 3) VTP 패스워드 일치 (인증)

 - VLAN 정보 공유 방법 : 'VTP Configuration Revision' 값이 높은 VTP 정보로 일치

 - VTP 모드 3가지 유형

1) VTP Server (기본 모드)

 - VLAN 생성/수정/삭제 가능 <- VLAN 데이터베이스 관리 권한 O
 - VLAN 정보를 전파(광고) O
 - VLAN 정보를 일치(대체) O
 - VLAN 정보를 전달(중계) O
 - Standard VLAN(1~1005) 생성 가능

2) VTP Client

 - VLAN 생성/수정/삭제 불가능
 - VLAN 정보를 전파(광고) X
 - VLAN 정보를 일치(대체) O
 - VLAN 정보를 전달(중계) O
 - 단, 'VTP Configuration Revision' 값이 높을때만 일치시킨다.

3) VTP Transparent (= VTP Disable)

 - VLAN 생성/수정/삭제 가능 <- VLAN 데이터베이스 관리 권한 O
 - VLAN 정보를 전파(광고) X
 - VLAN 정보를 일치(대체) X
 - VLAN 정보를 전달(중계) O
 - Standard VLAN(1~1005) & Extended VLAN(1006~4094) 생성 가능
 - VTP Configuration Revision 값이 항상 '0'으로 동작한다.
 - VTP Configuration Revision 값을 '0'으로 초기화할때 사용한다.

# VTP 설정 방법

1. Cisco IOS

Switch(config)# vtp domain CCNA
Switch(config)# vtp password cisco
Switch(config)# vtp mode [server|client|transparent]

2. Cat OS

Switch# vlan database
Switch(vlan)# vtp domain CCNA
Switch(vlan)# vtp password cisco
Switch(vlan)# vtp [server|client|transparent]
Switch(vlan)# exit

Ex) SW1은 VTP Server이며, SW2는 VTP Client로 구성하여, SW2는 SW1에서 생성한
     VLAN 15~17까지를 공유가 되도록하여라.

 - VTP Domain : CCNA
 - VTP Password : cisco

SW1#vlan database
SW1(vlan)#vtp domain CCNA
SW1(vlan)#vtp pass cisco
SW1(vlan)#vtp server
SW1(vlan)#exit

SW2#vlan database
SW2(vlan)#vtp dom CCNA
SW2(vlan)#vtp pass cisco
SW2(vlan)#vtp client
SW2(vlan)#exit

SW1# vlan database
SW1(vlan)# vlan 15
SW1(vlan)# vlan 16
SW1(vlan)# vlan 17
SW1(vlan)# exit

SW2#show vlan-switch brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                             active    Fa1/0, Fa1/2, Fa1/3, Fa1/4
                                                       Fa1/5, Fa1/6, Fa1/7, Fa1/8
                                                       Fa1/9, Fa1/10, Fa1/12, Fa1/13
                                                       Fa1/14, Fa1/15
11   VLAN_A                           active   
12   VLAN_B                           active   
13   VLAN_C                           active   
15   VLAN0015                         active   
16   VLAN0016                         active   
17   VLAN0017                         active   
1002 fddi-default                     active   
1003 token-ring-default             active   
1004 fddinet-default                  active   
1005 trnet-default                    active

SW1#show vtp status
VTP Version                     : 2
Configuration Revision          : 2
Maximum VLANs supported locally : 256
Number of existing VLANs        : 11
VTP Operating Mode              : Server
VTP Domain Name                 : CCNA
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x97 0x8C 0x40 0xDC 0x73 0xA3 0x01 0xF2
Configuration last modified by 13.13.1.1 at 3-1-02 00:44:18
Local updater ID is 13.13.1.1 on interface Vl1 (lowest numbered VLAN interface found)

SW2#show vtp status
VTP Version                     : 2
Configuration Revision          : 2
Maximum VLANs supported locally : 256
Number of existing VLANs        : 11
VTP Operating Mode              : Client
VTP Domain Name                 : CCNA
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x97 0x8C 0x40 0xDC 0x73 0xA3 0x01 0xF2
Configuration last modified by 13.13.1.1 at 3-1-02 00:44:18

SW1# vlan database
SW1(vlan)# no vlan 15
SW1(vlan)# no vlan 16
SW1(vlan)# no vlan 17
SW1(vlan)# exit

SW2#show vlan-switch brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                            active    Fa1/0, Fa1/2, Fa1/3, Fa1/4
                                                     Fa1/5, Fa1/6, Fa1/7, Fa1/8
                                                     Fa1/9, Fa1/10, Fa1/12, Fa1/13
                                                     Fa1/14, Fa1/15
11   VLAN_A                           active   
12   VLAN_B                           active   
13   VLAN_C                           active   
1002 fddi-default                     active   
1003 token-ring-default             active   
1004 fddinet-default                 active   
1005 trnet-default                    active

Ex) SW1은 VTP Server이며, SW2을 VTP Transparent로 변경하여라.

SW2# vlan database
SW2(vlan)# vtp transparent
SW2(vlan)# exit

SW2#show vtp status       
VTP Version                     : 2
Configuration Revision          : 0
Maximum VLANs supported locally : 256
Number of existing VLANs        : 8
VTP Operating Mode              : Transparent
VTP Domain Name                 : CCNA
VTP Pruning Mode                : Disabled
VTP V2 Mode                     : Disabled
VTP Traps Generation            : Disabled
MD5 digest                      : 0x7E 0xA6 0x7B 0xED 0x69 0x77 0x11 0x27
Configuration last modified by 13.13.1.1 at 3-1-02 00:48:41

 - SW1(VTP Server)에서 vlan 20~21 생성
 - SW2(VTP Transparent)에서 vlan 30~31 생성

SW1#show vlan-switch brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa1/1, Fa1/2, Fa1/3, Fa1/4
                                                Fa1/5, Fa1/6, Fa1/7, Fa1/8
                                                Fa1/9, Fa1/11, Fa1/12, Fa1/13
                                                Fa1/14, Fa1/15
11   VLAN_A                           active   
12   VLAN_B                           active   
13   VLAN_C                           active   
20   VLAN0020                         active   
21   VLAN0021                         active   
1002 fddi-default                     active   
1003 token-ring-default               active   
1004 fddinet-default                  active   
1005 trnet-default                    active   

SW2#show vlan-switch brief

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Fa1/0, Fa1/2, Fa1/3, Fa1/4
                                                Fa1/5, Fa1/6, Fa1/7, Fa1/8
                                                Fa1/9, Fa1/10, Fa1/12, Fa1/13
                                                Fa1/14, Fa1/15
11   VLAN_A                           active   
12   VLAN_B                           active   
13   VLAN_C                           active   
30   VLAN0030                         active   
31   VLAN0031                         active   
1002 fddi-default                     active   
1003 token-ring-default               active   
1004 fddinet-default                  active   
1005 trnet-default                    active   
SW2#

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# BPDU (Bridge Protocol Data Unit)

 - IEEE 802.1d STP가 지원되는 모든
   스위치들은 생성 및 전송 가능

 - 멀티케스트 2초 주기 전송 실시

 - BPDU 내용

1) Bridge-ID
2) Cost (10M=100, 100M=19, 1G=4, 10G=2)
3) Port-ID (128.x)
-------------------- 비교/선출 단위
4) Hello Time : 2초
5) Forward Delay Time : 15초
6) Max Age Time : 20초

 - Root Bridge가 선출되면 Root Bridge만
   Configuration BPDU를 생성하여 전송 실시

# IEEE 802.1d Spanning-Tree Protocol

 Bridge-ID : 64bit

 1) Priority : 16bit (기본값 : 32768)
 2) Mac Address : 48bit

1. Root Bridge 선출 (Bridge-ID 이용)

 1) Priority가 가장 낮은 스위치로 선출
 2) MAC 주소가 가장 낮은 스위치로 선출

2. 포트 선정 (Cost 값 이용)

 1) Root Port(RP) : BPDU 수신 포트
 2) Designated Port(DP) : BPDU 송신 포트

3. Blocking 포트 선정

 1) Cost 값이 높은 구간 포트 차단
 2) Sender Bridge ID가 높은 구간 포트 차단
 3) Port-ID가 높은 구간 포트 차단

SW1#show spanning-tree vlan 1 brief

VLAN1
  Spanning tree enabled protocol ieee
  Root ID    Priority    32768
             Address     c400.0bb8.0000
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     c400.0bb8.0000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/10     128.51   128    19 FWD     0 32768 c400.0bb8.0000 128.51
FastEthernet1/15     128.56   128    19 FWD     0 32768 c400.0bb8.0000 128.56

 - SW2를 Root Bridge로 선출하며, SW1 Fa1/15를 Blocking 하여라.

SW2(config)# spanning-tree vlan 1 priority 4096
SW3(config)# spanning-tree vlan 1 priority 16384

SW2#show spanning-tree vlan 1 brief

VLAN1
  Spanning tree enabled protocol ieee
  Root ID    Priority    4096
             Address     c401.0bb8.0000
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    4096
             Address     c401.0bb8.0000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/11     128.52   128    19 FWD     0  4096 c401.0bb8.0000 128.52
FastEthernet1/12     128.53   128    19 FWD     0  4096 c401.0bb8.0000 128.53

SW1#show spanning-tree vlan 1 brief

VLAN1
  Spanning tree enabled protocol ieee
  Root ID    Priority    4096
             Address     c401.0bb8.0000
             Cost        19
             Port        51 (FastEthernet1/10)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32768
             Address     c400.0bb8.0000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 0 

Interface                                   Designated
Name                 Port ID Prio Cost  Sts Cost  Bridge ID            Port ID
-------------------- ------- ---- ----- --- ----- -------------------- -------
FastEthernet1/10     128.51   128    19 FWD     0  4096 c401.0bb8.0000 128.52
FastEthernet1/15     128.56   128    19 BLK    19 16384 c402.0bb8.0000 128.55