Advanced STP

8/8/2019 Advanced STP

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Networking TechnologyNET 272 Lab Exercise

Advanced STP PVST+, RSTP, MST

Conducted on 9/16By: Chris Ortiz



Objective

The purpose of this lab is to configure and monitor STP features within a Cisco IOS environmentof switches.

Part 1: Connect Switched Network and Configure VLAN Operation

The network is configured as show below with associated port assignments (all at 100Mbps

ports connections):

As can be seen from the diagram above, there are three customer VLANs (Engineering-100,

Marketing-200 and Finance-100) and the management VLAN-1. After cabling the above configuration,

th t t i ki ith VLANS t th t th VLAN fi ti (d t b )



IP addressing was completed on physical, logical and loopback interfaces as shown in the earlier

network diagram. Additionally, we configured each access switch with a default gateway which

pointed to the SVI on the distribution switch. All access switches were also configured as VTP clients,

allowing the distribution switches serving as VTP clients.

Acc3(config)#vtp mode client Sets VTP to client mode

Acc3(config)#vtp domain team1Changing VTP domain name from cisco to team1 Sets the VTP domain name (must match)

Acc3(config)#vtp password cisco Sets the VTP domain password (must match)

Acc3(config-if)#spanning-tree portfast Forces an access port to immediately

transition to forwarding state

Access Switch ports were hard-coded to become access ports and put in the VLAN respective

to its connected host.

The distribution switches in the network were also configured with default gateways and

configured as VTP servers. We manually configure our trunking ports to trunk mode:

Acc3(config-if)#switchport trunk encapsulation dot1qAcc3(config-if)#switchport mode trunk

VLAN access could further be configured to restrict specific VLAN traffic:

Acc3(config-if)#switchport trunk allowed vlan 1,100,200,300

We verify trunking between access and distribution switches by executing the following command:

DS2#show int trunk

Port Mode Encapsulation Status Native vlanFa0/3 on 802.1q trunking 1Fa0/4 on 802.1q trunking 1Fa0/5 on 802.1q trunking 1

Port Vlans allowed on trunkFa0/3 1,100,200,300Fa0/4 1,100,200,300Fa0/5 1,100,200,300

Port Vlans allowed and active in management domainFa0/3 1,100,200,300Fa0/4 1,100,200,300Fa0/5 1 100 200 300



Acc3(config)#vtp mode server Sets VTP to server mode

Acc3(config)#vtp domain team1Changing VTP domain name from cisco to team1 Sets the VTP domain name (must match)

Acc3(config)#vtp password cisco Sets the VTP domain password (must match)

Finally, the VLANs are created on the distribution switches (VTP servers) and the VLAN

information is then propagated to the client (and server or transparent) switches participating in this

VTP instance.

We know that the only way for a host in one VLAN to pass traffic to a host in a different VLAN is

to introduce routing either statically or dynamically. In order to first tell a multi-layer switch that it

will perform as a layer 3 device, the following command must be issued:

DS2(config)#ip routing

At this point, devices within the same VLAN are able to communication with each other. We

verify this with ping commands.

Part 3 Configuring Routed Interfaces

Our next step to configure inter-VLAN traffic is to determine the means by which to route, in our

case by using EIGRP, a dynamic routing protocol. This is performed on all distribution switches:

DS1_3560_5(config)#router eigrp 1 Creates EIGRP routing instance

DS1_3560_5(config-router)#network 176.1.0.0 0.0.0.63DS1_3560_5(config-router)#network 176.1.0.64 0.0.0.63DS1_3560_5(config-router)#network 176.1.0.128 0.0.0.63DS1_3560_5(config-router)#network 176.1.0.192 0.0.0.15DS1_3560_5(config-router)#network 176.1.0.216 0.0.0.3DS1_3560_5(config-router)#network 176.1.0.220 0.0.0.3

Identifies networks (interfaces) that

will participate in the EIGRP routing

instance

Our next steps were to configure links between core and distribution as routed ports, configure

an ether-channel between the core switches, and verify operation of EIGRP:



requests. We finally rebooted the machine to resolve the issue, which led us to believe that the

workstation was possibly latched onto a previously configured IP address and network.

Our next step was to verify routing. Routing table from DS1 perspective looks like this:

DS1_3560_5#sho ip route

Gateway of last resort is not set

176.1.0.0/16 is variably subnetted, 11 subnets, 4 masksC 176.1.0.128/26 is directly connected, Vlan300D 176.1.0.254/32 [90/158720] via 176.1.0.213, 00:58:19, FastEthernet0/2D 176.1.0.224/30 [90/30720] via 176.1.0.213, 01:02:40, FastEthernet0/2

[90/30720] via 176.1.0.209, 01:02:40, FastEthernet0/1D 176.1.0.228/30 [90/30720] via 176.1.0.213, 01:02:40, FastEthernet0/2C 176.1.0.208/30 is directly connected, FastEthernet0/1C 176.1.0.212/30 is directly connected, FastEthernet0/2D 176.1.0.216/30 [90/28416] via 176.1.0.194, 01:02:41, Vlan1

[90/28416] via 176.1.0.130, 01:02:41, Vlan300[90/28416] via 176.1.0.66, 01:02:41, Vlan200[90/28416] via 176.1.0.2, 01:02:41, Vlan100

D 176.1.0.220/30 [90/28416] via 176.1.0.194, 01:02:41, Vlan1[90/28416] via 176.1.0.130, 01:02:41, Vlan300[90/28416] via 176.1.0.66, 01:02:42, Vlan200[90/28416] via 176.1.0.2, 01:02:42, Vlan100

C 176.1.0.192/28 is directly connected, Vlan1C 176.1.0.0/26 is directly connected, Vlan100C 176.1.0.64/26 is directly connected, Vlan200

We also confirm successful operation of the ether-channel:

6500_1_exit#sh etherchannelChannel-group listing:-----------------------

Group: 1----------Group state = L3Ports: 2 Maxports = 16Port-channels: 1 Max Port-channels = 16Protocol: LACP

At this point, we are able to successfully ping around the network and between VLANs.

Part 4 Monitoring the Network

In monitoring the network, well first observer spanning tree in operation between the access

and distribution switches, since these are connected with redundant links and susceptible to a loop

without STP running. The following page is a breakout of the results from a converged spanning tree



Core2 were to fail, access to the internet from this network would be unavailable, as well as access

from the internet to this network.



Documents

Advanced STP