Network&Cisco

Router TFTP Server

2009-11-09T14:33:00.003+02:00

Router'ımız HTTP ve FTP server olabildiği gibi TFTP hizmeti de verebilmektedir.
Bunun için server tarafında;

tftp-server flash:cat6500-entservices-mz.122-40.SG.bin

Client tarafında;

copy tftp://1.1.1.1/cat6500-entservices-mz.122-40.SG.bin null:

Router FTP Server

2009-11-09T14:25:00.004+02:00

Router'ımızı FTP server olarak yapılandırabilir ve çeşitli dosya kopyalama işlemlerimizi yapabiliriz. Örneğin güncellenmiş işimize yarayan IOS'u komşu router'dan FTP ile çekebiliriz. Bunun için server tarafında;

ftp-server enable
ftp-server topdir flash:
username ftp password ftp

Client tarafında;

ip ftp username ftp
ip ftp password ftp

Örneğin;
copy ftp://1.1.1.1/cat6500-entservices-mz.122-40.SG.bin null:

Router HTTP Server

2009-11-09T14:10:00.005+02:00

Router'imizi HTTP yani Web server yapabiliriz. Bunu neden yapalim ki demeyin, IOS yükleme veya test işlemleri için çok gerekli olabiliyor.

Server konfigirasyonu;

ip http server
ip http path flash:
username http password http

Client tarafında;

ip http client username http
ip http client password http

Örneğin;

copy http://1.1.1.1/cat6500-entservices-mz.122-40.SG.bin null:

OSPF Network Types

2009-10-30T09:23:00.000+02:00

OSPF'i öğrenmek için hangi network teknolojilerinde nasıl davranacağını bilmek zorundayız. Aynı zamanda network teknolojilerinin de OSPF'e nasıl davranacağını da bilmek zorundayız. Örneğin ethernet networklerde OSPF default olarak network tipi olarak "broadcast" seçip "hello"ları "Multicast" gönderirken "Frame-Relay"in doğasında multicast/broadcast yoktur. Oysaki OSPF komşuluk kurmak, DR-BDR seçmek isteyecektir. OSPF te bilinmesi gereken altın kurallardan biri de iki OSPF'in komşuluk kurabilmesi için "hello" ve "dead" timerların mutlaka eşleşmesi gerekir.

1- Broadcast:

R1(config-if)#do sh run int f0/0
Building configuration...

Current configuration : 110 bytes
!
interface FastEthernet0/0
ip address 1.1.1.1 255.255.255.0
ip ospf 1 area 0
duplex auto
speed auto
end

R2(config-if)#do sh run int f0/0
Building configuration...

Current configuration : 110 bytes
!
interface FastEthernet0/0
ip address 1.1.1.2 255.255.255.0
ip ospf 1 area 0
duplex auto
speed auto
end

Sonuçlar:

Default OSPF konfigirasyonu yaptığımızda asağıdaki "debug ip ospf hello" çıktısında da görüldüğü gibi R1, 224.0.0.5 adresine Multicast olarak hello gönderdi.

R1(config-if)#
*Mar 1 00:24:36.175: OSPF: Send hello to 224.0.0.5 area 0 on FastEthernet0/0 from 1.1.1.1

Asağıdaki çıktıya göre;

Ethernette default olarak network type "broadcast"tir.
Her 10 sn de bir "hello" gönderilir 40 sn hello alınmazsa komşuluk düşer.
DR-BDR seçimi yapılmış R1 DR olmuştur.

R1#show ip ospf interface
FastEthernet0/0 is up, line protocol is up
Internet Address 1.1.1.1/24, Area 0
Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
Enabled by interface config, including secondary ip addresses
Transmit Delay is 1 sec, State DR, Priority 1
Designated Router (ID) 1.1.1.1, Interface address 1.1.1.1
Backup Designated router (ID) 1.1.1.2, Interface address 1.1.1.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
oob-resync timeout 40
Hello due in 00:00:01
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 0, maximum is 1
Last flood scan time is 4 msec, maximum is 4 msec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 1.1.1.2 (Backup Designated Router)
Suppress hello for 0 neighbor(s)

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
1.1.1.2 1 FULL/BDR 00:00:30 1.1.1.2 FastEthernet0/0

2- Non-Broadcast:

Özellikle Frame Relay gibi non-broadcast multi access networklerde kullanılır. Bu tip netwoklerde multicast/broadcast olmadığı için "hello" paketleri gönderilemez haliyle komşuluk kurulamaz DR-BDR seçimi yapılamaz. Bu sorunu aşmak için OSPF paketlerini unicast göndermemiz gerekir bunu sağlamak içinde aşağıda görüldüğü gibi OSPF altında neighbor komutu ile HUB da SPOKE'ların adreslerini belirtmemiz gerekir. Yine SPOKE ların birbirleriyle R1 üzerinden haberleşebilmesi nedeniyle DR'ın mutlaka R1 olmasını sağlamak için interface altında "ip ospf priority 0" komutunu yazmamız gerekir.

!R1:

interface Loopback0

ip address 10.10.1.1 255.255.255.0

interface Serial1/0

ip address 10.10.123.1 255.255.255.0

encapsulation frame-relay

frame-relay map ip 10.10.123.2 102

frame-relay map ip 10.10.123.3 103

router ospf 1

network 0.0.0.0 255.255.255.255 area 0

neighbor 10.10.123.2

neighbor 10.10.123.3

!R2:

interface Loopback0

ip address 10.10.2.2 255.255.255.0

interface Serial1/0

ip address 10.10.123.2 255.255.255.0

encapsulation frame-relay

ip ospf priority 0

frame-relay map ip 10.10.123.1 201

frame-relay map ip 10.10.123.3 201

router ospf 1

network 0.0.0.0 255.255.255.255 area 0

!R3:

interface Loopback0

ip address 10.10.3.3 255.255.255.0

interface Serial1/0

ip address 10.10.123.3 255.255.255.0

encapsulation frame-relay

ip ospf priority 0

frame-relay map ip 10.10.123.1 301

frame-relay map ip 10.10.123.2 301

router ospf 1

network 0.0.0.0 255.255.255.255 area 0

Sonuçlar:

Hello paketleri unicast gönderilmektedir.

Frame Relay networklerde default network tipi non-broadcast' tir.

DR/BDR seçimi yapılmaktadır.

Timers: Hello 30, Dead 120

Neighbor komutu gereklidir.

*Mar 1 00:25:25.951: OSPF: Send hello to 10.10.123.2 area 0 on Serial1/0 from 10.10.123.1

*Mar 1 00:25:25.955: OSPF: Send hello to 10.10.123.3 area 0 on Serial1/0 from 10.10.123.1

R1#sh ip ospf interface s1/0

Serial1/0 is up, line protocol is up

Internet Address 10.10.123.1/24, Area 0

Process ID 1, Router ID 10.10.1.1, Network Type NON_BROADCAST, Cost: 64

Transmit Delay is 1 sec, State DR, Priority 1

Designated Router (ID) 10.10.1.1, Interface address 10.10.123.1

No backup designated router on this network

Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5

oob-resync timeout 120

Hello due in 00:00:01

Supports Link-local Signaling (LLS)

Index 1/1, flood queue length 0

Next 0x0(0)/0x0(0)

Last flood scan length is 1, maximum is 1

Last flood scan time is 0 msec, maximum is 4 msec

Neighbor Count is 2, Adjacent neighbor count is 2

Adjacent with neighbor 10.10.2.2

Adjacent with neighbor 10.10.3.3

Suppress hello for 0 neighbor(s)

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

10.10.2.2 0 FULL/DROTHER 00:01:34 10.10.123.2 Serial1/0

10.10.3.3 0 FULL/DROTHER 00:01:58 10.10.123.3 Serial1/0

3- Point-to-Point:

PPP, HDLC, Frame Relay Point-to-Point interfacelerde default OSPF network tipidir.

Timers: Hello 10, Dead 40
"sh ip ospf neighbor"ciktisinda da görüldüğü gibi DR/BDR seçimi yoktur.
Hello paketleri multicast olarak 224.0.0.5 adresine gönderilir.

*Mar 1 00:31:15.139: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0.12 from 10.1.12.1

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

10.10.2.2 0 FULL/ - 00:00:33 10.1.12.2 Serial1/0.12

R1#sh ip ospf interface s1/0.12

Serial1/0.12 is up, line protocol is up

Internet Address 10.1.12.1/24, Area 0

Process ID 1, Router ID 10.10.1.1, Network Type POINT_TO_POINT, Cost: 64

Transmit Delay is 1 sec, State POINT_TO_POINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

oob-resync timeout 40

Hello due in 00:00:02

Supports Link-local Signaling (LLS)

Index 1/1, flood queue length 0

Next 0x0(0)/0x0(0)

Last flood scan length is 1, maximum is 1

Last flood scan time is 0 msec, maximum is 0 msec

Neighbor Count is 1, Adjacent neighbor count is 1

Adjacent with neighbor 10.10.2.2

Suppress hello for 0 neighbor(s)

R1#sh run

interface Serial1/0

no ip address

encapsulation frame-relay

interface Serial1/0.12 point-to-point

ip address 10.1.12.1 255.255.255.0

frame-relay interface-dlci 102

4- Point to Multipoint Broadcast:

Hello'lar multicast olarak 224.0.0.5 adresine gönderilir.
Routing tablosuna /32'li host route'lar eklenir.
DR/BDR secimi yoktur.
Timers: Hello 30, Dead 120
Neighbor belirtmeye gerek yoktur.

*Mar 1 01:10:43.727: OSPF: Send hello to 224.0.0.5 area 0 on Serial1/0 from 10.10.123.1

R1#sh run
interface Serial1/0
ip address 10.10.123.1 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-multipoint
frame-relay map ip 10.10.123.2 102 broadcast
frame-relay map ip 10.10.123.3 103 broadcast
!

R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
O 10.10.3.3/32 [110/65] via 10.10.123.3, 00:01:41, Serial1/0
O 10.10.2.2/32 [110/65] via 10.10.123.2, 00:01:41, Serial1/0
C 10.10.1.0/24 is directly connected, Loopback0
O 10.10.123.3/32 [110/64] via 10.10.123.3, 00:01:41, Serial1/0
O 10.10.123.2/32 [110/64] via 10.10.123.2, 00:01:41, Serial1/0
C 10.10.123.0/24 is directly connected, Serial1/0

R1#sh ip osp int s1/0
Serial1/0 is up, line protocol is up
Internet Address 10.10.123.1/24, Area 0
Process ID 1, Router ID 10.10.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
oob-resync timeout 120
Hello due in 00:00:00
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 1, maximum is 1
Last flood scan time is 0 msec, maximum is 4 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 10.10.2.2
Adjacent with neighbor 10.10.3.3
Suppress hello for 0 neighbor(s)

R1#sh ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface
10.10.2.2 0 FULL/ - 00:01:35 10.10.123.2 Serial1/0
10.10.3.3 0 FULL/ - 00:01:33 10.10.123.3 Serial1/0

Detaylı bilgi için burayı tıklayabilirsiniz.

4- Point to Multipoint Non-Broadcast:

Hello'lar unicast gönderilir.
Routing tablosuna /32'li host route'lar eklenir.
DR/BDR secimi yoktur.
Timers: Hello 30, Dead 120
Nonbroadcast ortam olduğundan neighbor yazmak gereklidir.

R1#sh run
Building configuration...
!
interface Serial1/0
ip address 10.10.123.1 255.255.255.0
encapsulation frame-relay
ip ospf network point-to-multipoint non-broadcast
frame-relay map ip 10.10.123.2 102
frame-relay map ip 10.10.123.3 103
!
router ospf 1
network 0.0.0.0 255.255.255.255 area 0
neighbor 10.10.123.3
neighbor 10.10.123.2
!

*Mar 1 00:15:39.895: OSPF: Send hello to 10.10.123.3 area 0 on Serial1/0 from 10.10.123.1
*Mar 1 00:15:39.899: OSPF: Send hello to 10.10.123.2 area 0 on Serial1/0 from 10.10.123.1

R1#sh ip osp int s1/0
Serial1/0 is up, line protocol is up
Internet Address 10.10.123.1/24, Area 0
Process ID 1, Router ID 10.10.1.1, Network Type POINT_TO_MULTIPOINT, Cost: 64
Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT,
Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5
oob-resync timeout 120
Hello due in 00:00:26
Supports Link-local Signaling (LLS)
Index 1/1, flood queue length 0
Next 0x0(0)/0x0(0)
Last flood scan length is 2, maximum is 2
Last flood scan time is 0 msec, maximum is 4 msec
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 10.10.3.3
Adjacent with neighbor 10.10.2.2
Suppress hello for 0 neighbor(s)

R1#sh ip osp nei

Neighbor ID Pri State Dead Time Address Interface
10.10.3.3 0 FULL/ - 00:01:34 10.10.123.3 Serial1/0
10.10.2.2 0 FULL/ - 00:01:34 10.10.123.2 Serial1/0

R1#sh ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
O 10.10.3.3/32 [110/65] via 10.10.123.3, 00:17:46, Serial1/0
O 10.10.2.2/32 [110/65] via 10.10.123.2, 00:17:46, Serial1/0
C 10.10.1.0/24 is directly connected, Loopback0
O 10.10.123.3/32 [110/64] via 10.10.123.3, 00:17:46, Serial1/0
O 10.10.123.2/32 [110/64] via 10.10.123.2, 00:17:46, Serial1/0
C 10.10.123.0/24 is directly connected, Serial1/0

Olası Problemler:

Güzelce OSPF konfigirasyonu yaptınız fakat komşuluklar kurulmadığında ne yapabiliriz?
İlk yapmamız gereken şey "debug" açmaktır. Aşağıdaki örneğe bakarsak;

R2#debug ip ospf events
*Mar 1 00:33:09.583: OSPF: Mismatched hello parameters from 10.10.123.1
*Mar 1 00:33:09.587: OSPF: Dead R 120 C 40, Hello R 30 C 10

Görüldüğü gibi "hello" parametreleri uyuşmamıştır. Bu durumda OSPF network typle'larını kontrol edebiliriz veya bu parametlere manuel bir müdahale yapmamız gerekir.
Hatta konfigirasyona başlamadan önce sadece ilgili "debug"ları açarak kontrollu bir şekilde yolumuza devam edebiliriz, özellikle de "redistribution" yaparken "debug" çıktıları çok işimize yaramaktadır.

Konfigirayon Yedekleme ve Geri Alma (Configiration Archive and Rollback)

2009-10-23T11:01:00.000+03:00

Cisco cihazlarda konfigirasyon yedegi almak cok onemli ve mutlaka yapılması gereken bir iştir. Problem oluştuğunda önceki konfigirasyonlara dönebilmek sistemin arıza süresini kısaltarak EoC'i (end of career) önler:)

Bu işlemi yapmadan önce yedeği nereye nasil ve ne zaman alacağımıza karar vermemiz gerekir. Benim tavsiyem yedeklerin değişiklik yapıldığında ve güvenli bir ftp sunucuya alınmasıdır.

FTP sunucu ayarladıktan sonra kullanıcımızı oluşturalım:

ip ftp username mcap

ip ftp password secret

Bu islemden sonra yer ve zaman bilgilerini girelim:

Konfigirasyon değişikliği uyarıları ve kaydetme(Configiration change notification and logging)

2009-10-23T08:04:00.000+03:00

Cisco cihazlarda kimin hangi komutlari yürüttüğünü nasil anlarız?

Bu konu network yöneticileri için çok önemlidir. Özellikle probleme neden olan en son degisikliğin ne olduğunu ve kimin yaptığını bulma hususunda...

R1(config)#archive

R1(config-archive)#log config

R1(config-archive-log-cfg)#logging enable

R1(config-archive-log-cfg)#notify syslog

R1(config-archive-log-cfg)#hidekeys

005851: *Nov 1 16:46:57: %PARSER-5-CFGLOG_LOGGEDCMD: User:mcap logged command:no ip domain-lookup

R1#show archive log config all

idx sess user@line Logged command

1 1 mcap@vty0 | logging enable

2 1 mcap@vty0 | notify syslog

3 1 mcap@vty0 | hidekeys

4 2 mcap@vty0 |no ip domain-lookup

R1#show archive log config all provisioning

Switchlerde trafik kontrolu

2009-10-16T18:29:00.001+03:00

Storm-control ve srr-queue bandwith limit farkı:

Storm-control LAN a dogru alışılmışın dışındaki trafiklerin kontrol altına alınması amacına hizmet eden bir mekanizmadır. Cunkü bu kontrolsüz trafik performansı ciddi anlamda düşürür, wormlar sayesinde zaten çoğumuzun başından böyle bir hikaye geçmiştir. Yanda şekilde de görüldüğü gibi belirlenen eşik değerini aşan trafik normale yani eşik değerinin altına ininceye kadar bloklanir. Bu bloklama broadcast, multicast veya unicast trafik için yapılabilir. Bloklanan trafik için log tutulması güzel bir özelliktir. Eğer iki bloklama işlemi ayni anda ayarlanirsa bitanesinin eşik değerini geçmesi bloklama işlemi için yeterlidir. Trafik normale donunceye kadar ayarlanan 2 trafik işlemi icinde bloklama devam eder.
Asagidaki örnekte FastEthernet 0/1 trafigi 1Mb i geçerse bu değerin altına ininceye kadar trafik bloklanır.

Switch(config)# interface fastethernet0/1

Switch(config-if)# storm-control unicast level bps 1m

Ayrıntılı bilgi için burayı tıklayınız.

Switchlerde port bazli trafigi kontrol etmenin diger yoluda bir QoS mekanizmasi olan srr-queue bandwidth limit paremetresidir.
Switch uzerinde mls qos komutu ile servisi çalıştırdıktan sonra interface altinda komutu yazabiliriz. Örnegin FastEthernet 0/1 de trafigimizin %50 sini bloklamak istersek;

Switch(config)# interface fastethernet0/1

Switch(config-if)# srr-queue bandwidth limit 50

Yukarıda görüldüğü gibi interface den gecen trafigin yarisi drop edilecek sekilde ayarlama yapildi bu da 100Mb lik ethernet baglantisinin 50Mb lik kısmının kullanılabileceği anlamına gelir. Daha ayrıntılı bilgi için buraya tiklayiniz.

Sonuc olarak yukarıdada anlatıldıgı gibi switchlerimizde trafigimizi 2 yontemlede kontrol altına alabiliyoruz peki bu 2 yöntemin bir farkı varmı? Elbette var;
storm-control inbound yöndeki trafiği kontrol ederken, SRR diğer QoS mekanizmalarinda olduğu gibi giden trafiği kontrol etmemizi sağlar.

Routing_Distance_Redistribution

2009-07-29T15:37:00.000+03:00

Bu LAB'daki amacimiz Subedeki VOIP networkunun G.SHDSL devre uzerinden EIGRP ile, LAN networkunun LisedLine devre uzerinden OSPF ile birbirlerini yedekleyerek merkezle haberlesmesi.

Normal olarak bu yapida EIGRP nin Administrative Distance degeri (90), OSPF ten (110) kucuk oldugundan tum trafik EIGRP ile G.SHDSL devre uzerinden tasinmaktadir.

R2#sh ip route

O 10.1.13.0 [110/65] via 10.1.124.1, 00:51:48, FastEthernet0/0

C 10.1.23.0 is directly connected, Serial1/0

D 10.1.38.0 [90/2172416] via 10.1.23.3, 00:00:14, Serial1/0

D 10.1.37.0 [90/2172416] via 10.1.23.3, 00:00:14, Serial1/0

C 10.1.124.0 is directly connected, FastEthernet0/0

R1#sh ip route

C 10.1.13.0 is directly connected, Serial1/1

D 10.1.23.0 [90/2172416] via 10.1.124.2, 00:03:18, FastEthernet0/0

D 10.1.38.0 [90/2174976] via 10.1.124.2, 00:03:00, FastEthernet0/0

D 10.1.37.0 [90/2174976] via 10.1.124.2, 00:03:00, FastEthernet0/0

C 10.1.124.0 is directly connected, FastEthernet0/0

Ama bizim istedigimiz VOIP'in G.SHDSL ile LAN'in LisedLine ile tasinmasidir.

Tum networkler EIGRP ile R2 uzerinden merkeze tasindigina gore R2 uzerinde birseyler yapmamiz lazim. LAN networkunun LL devre uzerinden akmasi icin R2 deki EIGRP uzerinde LAN'a ait AD degerini OSPF AD degeri uzerinde cikarirsak zaten OSPF database'inde olan LAN networkunu R2'nin routing tablosuna sokabiliriz.

Once LAN networkunu bir ACL ile belirleyelim:

R2(config)#ip access-list standard LAN

R2(config-std-nacl)#permit 10.1.37.0 0.0.0.255

Simdide LAN networkunun EIGRP de distance degerini OSPF'in uzerine cikaralim:

R2(config)#router ei 1

R2(config-router)#distance 150 10.1.23.3 0.0.0.0 LAN

R2(config-router)#end

*Mar 1 01:21:17.567: %SYS-5-CONFIG_I: Configured from console by console

*Mar 1 01:21:17.647: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.23.3 (Serial1/0) is down: route configuration changed

*Mar 1 01:21:17.671: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.124.1 (FastEthernet0/0) is down: route configuration changed

R2#

*Mar 1 01:21:20.755: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.124.1 (FastEthernet0/0) is up: new adjacency

R2#

*Mar 1 01:21:59.343: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.23.3 (Serial1/0) is up: new adjacency

Routing tablosunu tekrar kontrol edelim:

R2#sh ip route

O 10.1.13.0 [110/65] via 10.1.124.1, 01:22:17, FastEthernet0/0

C 10.1.23.0 is directly connected, Serial1/0

D 10.1.38.0 [90/2172416] via 10.1.23.3, 00:01:53, Serial1/0

O 10.1.37.0 [110/66] via 10.1.124.1, 00:02:37, FastEthernet0/0

C 10.1.124.0 is directly connected, FastEthernet0/0

R1#sh ip route

C 10.1.13.0 is directly connected, Serial1/1

D 10.1.23.0 [90/2172416] via 10.1.124.2, 00:13:46, FastEthernet0/0

D 10.1.38.0 [90/2174976] via 10.1.124.2, 00:13:08, FastEthernet0/0

O 10.1.37.0 [110/65] via 10.1.13.3, 00:13:52, Serial1/1

C 10.1.124.0 is directly connected, FastEthernet0/0

Distance komutundaki 150 AD degeridir. 150 yapmamin nedeni OSPF'in AD degerinden (110) buyuk bir deger olmasidir yani 111 de olabilir.

Distance komutundaki diger bir parametre de "IP Source Address" EIGRP update'i aldigim komsumun adresidir.

Distance komutunda son olarak ta standart ACL ismini belirtiyoruz.

Son olarak R2 EIGRP tablosundaki route'larin merkezdeki OSPF'e duyrulmasi gerekir. Yedeklilik polikitamiz geregi LL devrenin kopmasi durumunda OSPF'in EIGRP route larini G.SHDSL devre uzerinden almasi gerekir.

R2(config)#router ospf 1

R2(config-router)#redistribute eigrp 1 subnets

R2(config-router)#end

R2#clear ip ospf process

Reset ALL OSPF processes? [no]: y

*Mar 1 01:43:09.251: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.124.1 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached

*Mar 1 01:43:09.251: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.124.4 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Interface down or detached

*Mar 1 01:43:09.383: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.124.1 on FastEthernet0/0 from LOADING to FULL, Loading Done

*Mar 1 01:43:09.383: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.124.4 on FastEthernet0/0 from LOADING to FULL, Loading Done

R4#sh ip route

O 10.1.13.0 [110/65] via 10.1.124.1, 00:00:21, FastEthernet0/0

O E2 10.1.23.0 [110/20] via 10.1.124.2, 00:00:21, FastEthernet0/0

O 10.1.38.0 [110/66] via 10.1.124.1, 00:00:21, FastEthernet0/0

O 10.1.37.0 [110/66] via 10.1.124.1, 00:00:21, FastEthernet0/0

C 10.1.124.0 is directly connected, FastEthernet0/0

LL devreyi kapatirsak:

R1(config)#int s1/1

R1(config-if)#shutdown

*Mar 1 01:52:53.299: %OSPF-5-ADJCHG: Process 1, Nbr 10.1.38.3 on Serial1/1 from FULL to DOWN, Neighbor Down: Interface down or detached

R1(config-if)#

*Mar 1 01:52:55.295: %LINK-5-CHANGED: Interface Serial1/1, changed state to administratively down

*Mar 1 01:52:56.295: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/1, changed state to down

R4#sh ip route

O E2 10.1.23.0 [110/20] via 10.1.124.2, 00:01:20, FastEthernet0/0

O E2 10.1.38.0 [110/20] via 10.1.124.2, 00:01:20, FastEthernet0/0

O E2 10.1.37.0 [110/20] via 10.1.124.2, 00:01:20, FastEthernet0/0

C 10.1.124.0 is directly connected, FastEthernet0/0

G.SHDSL devreyi kapatalim:

R2(config)#int s1/0

R2(config-if)#shutdown

R2(config-if)#

*Mar 1 01:56:58.659: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.23.3 (Serial1/0) is down: interface down

R2(config-if)#

*Mar 1 01:57:00.523: %LINK-5-CHANGED: Interface Serial1/0, changed state to administratively down

*Mar 1 01:57:01.523: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial1/0, changed state to down

R4#sh ip route

O 10.1.13.0 [110/65] via 10.1.124.1, 00:01:36, FastEthernet0/0

O 10.1.38.0 [110/66] via 10.1.124.1, 00:01:36, FastEthernet0/0

O 10.1.37.0 [110/66] via 10.1.124.1, 00:01:36, FastEthernet0/0

C 10.1.124.0 is directly connected, FastEthernet0/0

SPANNING-TREE LOAD SHARING

2008-09-10T07:00:00.000+03:00

SPANNING-TREE LOAD SHARING

Bu lab Dynamips te yapilmistir.

Bu lab'da amaclanan Trunk portlarda Vlan lari dagitip bir anlamda 2. katmanda load balance yada load sharing yada yuk paylastirma yapmaktir.

Her SW de yapilmasi gereken conf :

conf t

hostname SWx

vtp file nvram:vlan.dat

line console 0

loggin syn

end

vlan database

vtp server

vtp domain CCIE

! asagidaki vlanlarin sadece VTP server da olusturulmasi yeterlidir.

vlan 10

vlan 20

vlan 30

vlan 40

exit

SW1#conf t

SW1(config)#vtp file nvram:vlan.dat

SW1(config)#end

SW1#sh cdp neighbors | b SW3

SW3 Fas 1/12 157 R S I 3640 Fas 1/9

SW3 Fas 1/11 157 R S I 3640 Fas 1/8

SW3 Fas 1/10 157 R S I 3640 Fas 1/7

Gereksiz portlari kapatip CDP ile elde ettgimiz bilgilerle ilgili portlari Trunk yapiyoruz.

SW1(config)#int range f1/0 - 15

SW1(config-if-range)#shut

SW1(config-if-range)#int range f1/10 - 11

SW1(config-if-range)#no shut

SW1(config-if-range)#switchport trunk encapsulation dot1q

SW1(config-if-range)#switchport mode trunk

*Mar 1 00:20:56.495: %DTP-5-TRUNKPORTON: Port Fa1/10-11 has become dot1q trunk

SW1#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/10 on 802.1q trunking 1

Fa1/11 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/10 1-1005

Fa1/11 1-1005

Port Vlans allowed and active in management domain

Fa1/10 1,10,20,30,40

Fa1/11 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/10 1,10,20,30,40

Fa1/11 1,10,20,30,40

SW3#sh cdp neighbors | b SW1

SW1 Fas 1/8 149 R S I 3640 Fas 1/11

SW1 Fas 1/7 149 R S I 3640 Fas 1/10

SW3#sh cdp neighbors | b SW4

SW4 Fas 1/15 146 R S I 3640 Fas 1/15

SW4 Fas 1/14 146 R S I 3640 Fas 1/14

SW4 Fas 1/13 146 R S I 3640 Fas 1/13

SW3(config)#int range f1/0 - 15

SW3(config-if-range)#shut

SW3(config-if-range)#int range f1/7 - 8 , f1/13 - 14

SW3(config-if-range)#no shut

SW3(config-if-range)#switchport trunk encap dot1q

SW3(config-if-range)#switchport mode trunk

SW3#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/7 on 802.1q trunking 1

Fa1/8 on 802.1q trunking 1

Fa1/13 on 802.1q trunking 1

Fa1/14 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/7 1-1005

Fa1/8 1-1005

Fa1/13 1-1005

Fa1/14 1-1005

Port Vlans allowed and active in management domain

Fa1/7 1,10,20,30,40

Fa1/8 1,10,20,30,40

Fa1/13 1,10,20,30,40

Fa1/14 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/7 1,10,20,30,40

Fa1/8 none

Fa1/13 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/14 1,10,20,30,40

!SW4

SW4#sh cdp neighbors

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

SW2 Fas 1/12 125 R S I 3640 Fas 1/15

SW2 Fas 1/11 125 R S I 3640 Fas 1/14

SW2 Fas 1/10 125 R S I 3640 Fas 1/13

SW3 Fas 1/14 143 R S I 3640 Fas 1/14

SW3 Fas 1/13 143 R S I 3640 Fas 1/13

SW4(config)#int range f1/0 - 15

SW4(config-if-range)#shut

SW4(config-if-range)#int range f1/10 - 11 , f1/13 - 14

SW4(config-if-range)#switchport trunk encap dot1q

SW4(config-if-range)#switchport mode trunk

SW4(config-if-range)#no shut

SW4#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/10 on 802.1q trunking 1

Fa1/11 on 802.1q trunking 1

Fa1/13 on 802.1q trunking 1

Fa1/14 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/10 1-1005

Fa1/11 1-1005

Fa1/13 1-1005

Fa1/14 1-1005

Port Vlans allowed and active in management domain

Fa1/10 1,10,20,30,40

Fa1/11 1,10,20,30,40

Fa1/13 1,10,20,30,40

Fa1/14 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/10 1,10,20,30,40

Fa1/11 1,10,20,30,40

Fa1/13 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/14 none

! SW2

SW2#sh cdp neighbors

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

SW4 Fas 1/14 142 R S I 3640 Fas 1/11

SW4 Fas 1/13 142 R S I 3640 Fas 1/10

SW2(config)#int range f1/13 - 14

SW2(config-if-range)#switchport trunk encapsulation dot1q

SW2(config-if-range)#switchport mode trunk

SW2(config-if-range)#no shut

*Mar 1 00:54:52.475: %DTP-5-TRUNKPORTON: Port Fa1/13-14 has become dot1q trunk

SW2#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/13 on 802.1q trunking 1

Fa1/14 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/13 1-1005

Fa1/14 1-1005

Port Vlans allowed and active in management domain

Fa1/13 1,10,20,30,40

Fa1/14 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/13 1,10,20,30,40

Fa1/14 none

Asagidaki sekilde default ayarlarla tafik akisi kirmizi ile cizilen yerlerde gosterilmistir.

Sekle gore neden bazi portlarin Forwarding (root port yada designated port) oldugunu aciklayalim.

STP hangi portunun block yada designated olacagina nasil karar verir?

Ortamdaki en dusuk bridge ID li Switch Root secildikten sonra BPDU trafigi baslar. Root Switch tarafindan gonderilenler superior BPDU lardir. Superior BPDU alan Switchler asagidaki kriterlere gore hangi portunun block yada designated (Forward) olacagina karar verir.

1- A lower Root Bridge ID.

2- A lower path cost to the Root.

3- A lower Sending Bridge ID.

4- A lower Sending Port ID.

Root birdge in tum portlari forwarding moddadir. 1. kriter ile block port karari verilemezse sonraki adimda asagida sekilde gorulen cost degerleri baz alinir. Cost degeri kucuk olan port Root portdur ve forwarding moda gecer. Cost degerleri esitse BPDU alinan Bridge ID si kucuk olan port, oda esitse bagli SW nin kucuk portuna bagli port root port olur ve forwarding moda gecer.

Bandwidth	STP Cost Value
4 Mbps	250
10 Mbps	100
16 Mbps	62
45 Mbps	39
100 Mbps	19
155 Mbps	14
622 Mbps	6
1 Gbps	4
10 Gbps	2

Buraya kadar tum SW lerde Vlan lari ve Trunklari olusturduk. Simdi STP ayarlariyla oynayarak VLAN 10 ve 30 un buyuk olan Trunk portlardan, diger VLAN larin kucuk olan Trunk portlardan akmasini saglayarak kismen Load Sharing islemini yapacagiz.

Ilk durumda asagida da goruldugu gibi SW1 root tur.

SW1#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 32768 cc00.0e34.0000 0 2 20 15 This bridge is root

VLAN10 32768 cc00.0e34.0001 0 2 20 15 This bridge is root

VLAN20 32768 cc00.0e34.0002 0 2 20 15 This bridge is root

VLAN30 32768 cc00.0e34.0003 0 2 20 15 This bridge is root

VLAN40 32768 cc00.0e34.0004 0 2 20 15 This bridge is root

SW2#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 32768 cc00.0e34.0000 57 2 20 15 FastEthernet1/13

VLAN10 32768 cc00.0e34.0001 57 2 20 15 FastEthernet1/13

VLAN20 32768 cc00.0e34.0002 57 2 20 15 FastEthernet1/13

VLAN30 32768 cc00.0e34.0003 57 2 20 15 FastEthernet1/13

VLAN40 32768 cc00.0e34.0004 57 2 20 15 FastEthernet1/13

SW3#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 32768 cc00.0e34.0000 19 2 20 15 FastEthernet1/7

VLAN10 32768 cc00.0e34.0001 19 2 20 15 FastEthernet1/7

VLAN20 32768 cc00.0e34.0002 19 2 20 15 FastEthernet1/7

VLAN30 32768 cc00.0e34.0003 19 2 20 15 FastEthernet1/7

VLAN40 32768 cc00.0e34.0004 19 2 20 15 FastEthernet1/7

SW4#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 32768 cc00.0e34.0000 38 2 20 15 FastEthernet1/13

VLAN10 32768 cc00.0e34.0001 38 2 20 15 FastEthernet1/13

VLAN20 32768 cc00.0e34.0002 38 2 20 15 FastEthernet1/13

VLAN30 32768 cc00.0e34.0003 38 2 20 15 FastEthernet1/13

VLAN40 32768 cc00.0e34.0004 38 2 20 15 FastEthernet1/13

SW1 in Root bridge olmasinin nedeni tum SW lerin priority leri ayni (32768) olmasi ile Bridge ID (lowest MAC adress) sinin kucuk olmasindandir ve Root olmasinin sonucunda tum portlari FW moddadir.

SW1#sh spanning-tree brief

VLAN1

Spanning tree enabled protocol ieee

Root ID Priority 32768

Address cc00.0e34.0000

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32768

Address cc00.0e34.0000

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/10 128.51 128 19 FWD 0 32768 cc00.0e34.0000 128.51

FastEthernet1/11 128.52 128 19 FWD 0 32768 cc00.0e34.0000 128.52

Asagidaki SW3 ornegimizde kendi bridge priority si buyuk oldugundan (cc02>cc00) SW1 in root bridge oldugunu kabul etmistir.

SW3#sh spanning-tree bri

VLAN1

Spanning tree enabled protocol ieee

Root ID Priority 32768

Address cc00.0e34.0000

Cost 19

Port 48 (FastEthernet1/7)

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32768

Address cc02.0e34.0000

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 300

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/7 128.48 128 19 FWD 0 32768 cc00.0e34.0000 128.51

FastEthernet1/8 128.49 128 19 BLK 0 32768 cc00.0e34.0000 128.52

FastEthernet1/13 128.54 128 19 FWD 19 32768 cc02.0e34.0000 128.54

FastEthernet1/14 128.55 128 19 FWD 19 32768 cc02.0e34.0000 128.55

Simdi load sharing icin Vlan 10 ve 30 icin Root bridge’in SW1 digerleri icin SW2 olmasini saglayalim.

SW1(config)#spanning-tree vlan 10 root primary

% This switch is already the root of VLAN10 spanning tree

VLAN 10 bridge priority set to 8192

VLAN 10 bridge max aging time unchanged at 20

VLAN 10 bridge hello time unchanged at 2

VLAN 10 bridge forward delay unchanged at 15

SW1(config)#spanning-tree vlan 30 root primary

% This switch is already the root of VLAN30 spanning tree

VLAN 30 bridge priority set to 8192

VLAN 30 bridge max aging time unchanged at 20

VLAN 30 bridge hello time unchanged at 2

VLAN 30 bridge forward delay unchanged at 15

Bu komutla SW1’in bridge priority leri 4 kat asagi cekilerek bu Vlanlarda root bridge olmasi garantilenmektedir. Diger Vlan larda SW2 yi root bridge yapmak icin;

SW2(config)#spanning-tree vlan 1 root primary

VLAN 1 bridge priority set to 8192

VLAN 1 bridge max aging time unchanged at 20

VLAN 1 bridge hello time unchanged at 2

VLAN 1 bridge forward delay unchanged at 15

SW2(config)#spanning-tree vlan 20 root primary

VLAN 20 bridge priority set to 8192

VLAN 20 bridge max aging time unchanged at 20

VLAN 20 bridge hello time unchanged at 2

VLAN 20 bridge forward delay unchanged at 15

SW2(config)#spanning-tree vlan 40 root primary

VLAN 40 bridge priority set to 8192

VLAN 40 bridge max aging time unchanged at 20

VLAN 40 bridge hello time unchanged at 2

VLAN 40 bridge forward delay unchanged at 15

Simdiki durum;

SW1#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 8192 cc01.0e34.0000 57 2 20 15 FastEthernet1/10

VLAN10 8192 cc00.0e34.0001 0 2 20 15 This bridge is root

VLAN20 8192 cc01.0e34.0002 57 2 20 15 FastEthernet1/10

VLAN30 8192 cc00.0e34.0003 0 2 20 15 This bridge is root

VLAN40 8192 cc01.0e34.0004 57 2 20 15 FastEthernet1/10

SW1#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/10 on 802.1q trunking 1

Fa1/11 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/10 1-1005

Fa1/11 1-1005

Port Vlans allowed and active in management domain

Fa1/10 1,10,20,30,40

Fa1/11 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/10 1,10,20,30,40

Fa1/11 10,30

SW2#sh spanning-tree root brief

Root Hello Max Fwd

Vlan Root ID Cost Time Age Delay Root Port

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

VLAN1 8192 cc01.0e34.0000 0 2 20 15 This bridge is root

VLAN10 8192 cc00.0e34.0001 57 2 20 15 FastEthernet1/13

VLAN20 8192 cc01.0e34.0002 0 2 20 15 This bridge is root

VLAN30 8192 cc00.0e34.0003 57 2 20 15 FastEthernet1/13

VLAN40 8192 cc01.0e34.0004 0 2 20 15 This bridge is root

SW2#sh int trunk

Port Mode Encapsulation Status Native vlan

Fa1/13 on 802.1q trunking 1

Fa1/14 on 802.1q trunking 1

Port Vlans allowed on trunk

Fa1/13 1-1005

Fa1/14 1-1005

Port Vlans allowed and active in management domain

Fa1/13 1,10,20,30,40

Fa1/14 1,10,20,30,40

Port Vlans in spanning tree forwarding state and not pruned

Fa1/13 1,10,20,30,40

Fa1/14 1,20,40

Bu asamada SW1’i Vlan 10 ve 30 da, SW2 yide 1, 20, 40 nolu Vlanlarda root bridge yaptik fakat hala tum trafik Sekil 2 deki gibi kucuk olan portlardan akmaya devam ediyor. Oysaki bizim amacimiz Vlan 10 ve 30 un buyuk olan portlardan diger Vlanlarin kucuk olan portlardan akmasini saglamak.

Duzenleme yapmadan once:

SW1#sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/10 128.51 128 19 FWD 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/11 128.52 128 19 FWD 0 8192 cc00.0fc4.0001 128.52

SW3#sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/7 128.48 128 19 FWD 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/8 128.49 128 19 BLK 0 8192 cc00.0fc4.0001 128.52

Yukarida kirmizi olarak gosterdigim gibi Fa1/10 un priority si daha dusuk yani daha degerlidir. Dolayisiyla bu portla birlikte diger SW ye bagli port da root port olur. Vlan 10 ve 30 u buyuk numarali yani Fa1/11 den gecirmek icin ya bu portun priority sini dusurerek yada Fa1/10 unun degerini artirarak Fa1/11’i daha degerli hale getirmemiz gerekir. Ben degerini kucultmeyi tercih ettim defaultu 128.

SW1(config)#int f1/11

SW1(config-if)#spanning-tree vlan 10 port-priority 124

SW1(config-if)# do sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/10 128.51 128 19 FWD 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/11 124.52 124 19 FWD 0 8192 cc00.0fc4.0001 124.52

Yukarida goruldugu gibi Fa1/11’in Priority’si duserek degerli daha degerli hale geldi. Degerleri 4 un katlari seklinde azaltabiliyoruz.

SW3#sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/7 128.48 128 19 BLK 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/8 128.49 128 19 FWD 0 8192 cc00.0fc4.0001 124.52

Priority’nin esas etkisi karsi SW portunda oldu. Priority degerini kucultmeden once block modda olan port Forward moda gecti, loop’u onlemek icin bu sefer diger port block moda gecti. Vlan 10 da SW1 root bridge oldugu icin portlarinin ikisi de forward modda kaldi.

Bu islemi SW3 te path cost degerini degistirerek te yapabiliriz:

SW3#sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/7 128.48 128 19 FWD 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/8 128.49 128 19 BLK 0 8192 cc00.0fc4.0001 128.52

SW3(config-if)#int f1/8

SW3(config-if)#spanning-tree vlan 10 cost 18

SW3(config-if)#do sh spanning-tree vlan 10 brie

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/7 128.48 128 19 BLK 0 8192 cc00.0fc4.0001 128.51

FastEthernet1/8 128.49 128 18 FWD 0 8192 cc00.0fc4.0001 128.52

Yine ayni mantikla SW3 ile SW4 arasinda SW3 un Vlan 10 icin portlari FW modda. SW4 te ise yine kucuk port olan Fa1/13 ten akan trafik icin ya F1/13 un costunu artirip yada F1/14 un costunu dusurerek trafigin buyuk olan F1/14 ten akmasini saglayabiliriz.

SW4(config-if)#int f1/14

SW4(config-if)#spanni vlan 10 cost 18

SW4(config-if)#do sh spann vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/13 128.54 128 19 BLK 18 32768 cc02.0fc4.0001 128.54

FastEthernet1/14 128.55 128 18 FWD 18 32768 cc02.0fc4.0001 128.55

SW2 ile SW4 arasindaki segmentte ayni taktiktle trafigi buyuk olan porta yonlendiriyoruz.

SW4(config-if)#int f1/11

SW4(config-if)#spanning-tree vlan 10 port-priority 124

SW4(config-if)#do sh spann vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/10 128.51 128 19 FWD 36 32768 cc03.0fc4.0001 128.51

FastEthernet1/11 124.52 124 19 FWD 36 32768 cc03.0fc4.0001 124.52

Sonuc olarak buyuk olan F1/14 portu forward moda gecerek Vlan 10 icin tum trafik buyuk olan portlara yonlendirmis olduk. Vlan 30 icin de ayni adimlari yaparak Bulent Hocamin verdigi odevi yapmis oluyorum.

SW2#sh spanning-tree vlan 10 brief

Interface Designated

Name Port ID Prio Cost Sts Cost Bridge ID Port ID

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

FastEthernet1/13 128.54 128 19 BLK 36 32768 cc03.0fc4.0001 128.51

FastEthernet1/14 128.55 128 19 FWD 36 32768 cc03.0fc4.0001 124.52

Priority veya path cost degerleri ile Vlan lari farkli trunklardan gondermek "allowed vlan" tanimlamalari yapmaktan daha avantajlidir. Bir portun down olmasi dusumunda trafik diger porttan akmaya devam eder.

Bu yontemle load balancing yapmanin dezavantaji da vardir. Bir porta yonlendirilen trafigin o portun kapasitesinin asmasi durumunda asan trafik diger porta gecmez, oysaki diger vlan larin aktigi bir baska port atil durumda olabilir. Cisco bu dezavantaji ortadan kaldirmak icin "etherchannel" tavsiye etmektedir. Bana bir odev daha mi cikti acaba:)

!!!NOT: Lutfen port altinda konfigirasyon yaparken Vlan numarasini yazmayi unutmayin, aksi takdirde yazdiginiz deger tum Vlan lar icin gecerli olur. Ben yaptim ordan biliyorumJ

Kaynak: Btegitim CCIE Boot Camp ders notlari, Bulent Hoca’nin anlattiklarindan aklimda kalanlar ve ofcourse cisco.com

10 Eylul 2008 Carsamba

mesutcap@gmail.com