W&L Page 1 CCNA CCNA Training 2.8 Identify enhanced switching technologies Jose Luis Flores / Amel Walkinshaw Aug, 2015

W&L Page 2 CCNA LAN Switching Technologies 2.8 Identify enhanced switching technologies 2.8.a RSTP 2.8.b PVSTP 2.8.c Etherchannels

W&L Page 3 CCNA Identify enhanced switching technologies The 802.1D Spanning Tree Protocol (STP) standard was designed at a time when the recovery of connectivity after an outage within a minute or so was considered adequate performance. With the advent of Layer 3 switching in LAN environments, bridging now competes with routed solutions where protocols, such as Open Shortest Path First (OSPF) and Enhanced Interior Gateway Routing Protocol (EIGRP), are able to provide an alternate path in less time.

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W&L Page 6 CCNA Identify enhanced switching technologies Which switch provides the spanning-tree designated port role for the network segment that services the printers? A. Switch1 B. Switch2 C. Switch3 D. Switch4

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W&L Page 8 CCNA udld aggressive spanning-tree mode rapid-pvst spanning-tree portfast default spanning-tree portfast bpduguard default no spanning-tree optimize bpdu transmission On interface: description XXXXX power inline never switchport access vlan XXX switchport mode access no logging event link-status no snmp trap link-status no mdix auto spanning-tree portfast spanning-tree guard loop Check Bug CSCee70806 at ____________________ Release Notes "no spanning-tree optimize bpdu transmission" cannot be removed from the "show running" output. Best practices:

W&L Page 9 CCNA Best practices: errdisable recovery cause udld errdisable recovery cause bpduguard errdisable recovery interval (time in seconds)

W&L Page 10 CCNA PVST Operation  In a PVST+ environment, you can tune the spanning-tree parameters so that half the VLANs forward on each uplink trunk.  You do this by configuring one switch to be elected the root bridge for hal of the VLANs in the network and a second switch to be elected the root bridge for the other half of the VLANs

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W&L Page 12 CCNA PVST Operation  Switched networks running PVST+ have the following characteristics: −Configured PVST per VLAN allows redundant links to be fully utilized. −Each additional spanning-tree instance for a VLAN adds more CPU cycles to all switches in the network

W&L Page 13 CCNA PVST Operation PVST Port States Operation AllowedBlockingListeningLearningForwardingDisabled Can receive and process BPDUs Yes No Can forward data frames received on interface No YesNo Can forward data frames switched from another interface No YesNo Can learn MAC addresses No Yes NO

W&L Page 14 CCNA PVST Operation Extended System ID

W&L Page 15 CCNA PVST Operation Bridge ID for PVST+ with Extended System ID

W&L Page 16 CCNA Rapid PVST + Operation  In Rapid PVST+, a single instance of RSTP runs for each VLAN. This is why Rapid PVST+ has a very high demand for switch resources (CPU cycles and RAM)  Rapid PVST+ is simply the Cisco Implementation of RSTP on a per-VLAN basis.

W&L Page 17 CCNA Rapid PVST + Operation  With RSTP, IEEE improved the convergence performance of STP from 50 seconds to less than 10 seconds with its definition of Rapid STP (RSTP) in the standard 802.1w.

W&L Page 18 CCNA Which two states are the port states when RSTP has converged? (Choose two. ) A. discarding B. listening C. learning D. forwarding E. disabled 2.8 Identify enhanced switching technologies

W&L Page 19 CCNA Rapid PVST + Operation  RSTP is identical to STP in the following ways:  It elects the root switch using the same parameters and tiebreakers.  It elects the root port on non-root switches with the same rules.  It elects designated ports on each LAN segment with the same rules.  It places each port in either forwarding or discarding state, although RSTP calls the blocking state the discarding state.

W&L Page 20 CCNA RSTP and STP Port States Operationa l State STP State 802.1D RSTP State 802.1w Forwards Data Frames in This State? EnabledBlockingDiscardingNo EnabledListeningDiscardingNo EnabledLearning No EnabledForwarding Yes Disabled DiscardingNo

W&L Page 21 CCNA Identify enhanced switching technologies Port Roles The role is now a variable assigned to a given port. The root port and designated port roles remain, while the blocking port role is split into the backup and alternate port roles. The Spanning Tree Algorithm (STA) determines the role of a port based on Bridge Protocol Data Units (BPDUs). In order to simplify matters, the thing to remember about a BPDU is there is always a method to compare any two of them and decide whether one is more useful than the other. This is based on the value stored in the BPDU and occasionally on the port on which they are received. This considered, the information in this section explains practical approaches to port roles.

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W&L Page 24 CCNA Identify enhanced switching technologies EtherChannel mode ON

W&L Page 25 CCNA Identify enhanced switching technologies Ciscozine_SW1 Ciscozine_SW1# configure terminal Ciscozine_SW1(config)# interface range fastethernet0/0 -2 Ciscozine_SW1(config-if-range)# switchport mode trunk Ciscozine_SW1(config-if-range)# switchport access vlan 10 Ciscozine_SW1(config-if-range)# channel-group 1 mode on Ciscozine_SW1(config-if-range)# exit Ciscozine_SW1(config)# exit Ciscozine_SW1# write Ciscozine_SW2 Ciscozine_SW2# configure terminal Ciscozine_SW2(config)# interface range fastethernet0/0 -2 Ciscozine_SW2(config-if-range)# switchport mode trunk Ciscozine_SW2(config-if-range)# switchport access vlan 10 Ciscozine_SW2(config-if-range)# channel-group 1 mode on Ciscozine_SW2(config-if-range)# exit Ciscozine_SW2(config)# exit Ciscozine_SW2# write

W&L Page 26 CCNA Identify enhanced switching technologies STP/EtherChannel Cost Spanning-tree reproduces the increased bandwidth provided by EtherChannel. The default cost for a 100 Mbps link is 19 and if a port-channel is created that has only two 100 Mbps links, the spanning-tree cost will be 9. A port-channel with six or more 100 Mbps physical ports will have an STP cost of 5. The cost is calculated based on the number of ports assigned to the port-channel. see table below:

W&L Page 27 CCNA Identify enhanced switching technologies A network administrator is configuring an EtherChannel between SW1 and SW2. The SW1 configuration is shown. What is the correct configuration for SW2? A. interface FastEthernet 0/1 channel-group 1 mode active switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode active switchport trunk encapsulation dot1q switchport mode trunk B. interface FastEthernet 0/1 channel-group 2 mode auto switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 2 mode auto switchport trunk encapsulation dot1q switchport mode trunk C. interface FastEthernet 0/1 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode desirable switchport trunk encapsulation dot1q switchport mode trunk D. interface FastEthernet 0/1 channel-group 1 mode passive switchport trunk encapsulation dot1q switchport mode trunk interface FastEthernet 0/2 channel-group 1 mode passive switchport trunk encapsulation dot1q switchport mode trunk

W&L Page 28 CCNA Identify enhanced switching technologies What parameter can be different on ports within an EtherChannel? A. speed B. DTP negotiation settings C. trunk encapsulation D. duplex

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W&L Page 30 CCNA Identify enhanced switching technologies If the devices produced the given output, what is the cause of the EtherChannel problem? A. SW1's Fa0/1 interface is administratively shut down. B. There is an encapsulation mismatch between SW1's Fa0/1 and SW2's Fa0/1 interfaces. C. There is an MTU mismatch between SW1's Fa0/1 and SW2's Fa0/1 interfaces. D. There is a speed mismatch between SW1's Fa0/1 and SW2's Fa0/1 interfaces.

W&L Page 31 CCNA Identify enhanced switching technologies A network administrator creates a layer 3 EtherChannel, bundling four interfaces into channel group1. On what interface is the IP address configured? A. the port-channel 1 interface B. the highest number member interface C. all member interfaces D. the lowest number member interface

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W&L Page 33 CCNA Q&A