CCIE Routing & Switching Version 5.0 - Layer 2

Includes some of the basic switching topics covered in CCNA

In this video, you get introduced to VLAN basics

Configuring static vlan and verifying with show vlan commands

How the dynamic VLAN works

here, i will be discussing on the concept of Trunking, why there is a need for trunking, and protocols used

Verify trunking cofigurations with labs

in this video you get introduced to Extended vlan ranges and also voice vlan uses and configuration basics

In this video, we see the need for intervlan routing, and also we will see legacy method of inter vlan routing

using subinterfaces how can we do inter vlan routing covered here. and also useful to understand how ccie exam topology built

The most common method now a days used for inter vlan routing, Faster and scalable. and also we will see using switchport as layer 3 router port

VTp allow us to synchronize the vlan information . we will see different modes supported.

Basic pre-requisuite for VTP lab verification

configure and Verify VTP modes

understand the concept of pruning and how it helps to optimize broadcast or unicast

in this video will see how can we modify the default pruning list and also manual pruning

VTP version 3 add some more enhancements to new IOS, we will see overview of all those features and verify them later on videos with labs

VTP version 3 add some more enhancements to new IOS, we will see overview of all those features and verify them on synchronizing vlan information

VTP version 3 add some more enhancements to new IOS, we will see overview of all those features and verify them on synchronizing MSTP and private vlan information

If a packet is received on a dot1q link, that does not have VLAN tagged, it is assumed that it belongs to native VLAN.

Default native vlan is VLAN 1

Redundant link between switches provides redundancy.

Also possibility to create loops when switches do broadcasts.

1.Broadcast storms

2.Mac-table instability

3.Multiple frame transmissions

}STP stop the loops which occurs when you have multiple links between switches

}STP stops avoiding Broadcast Storms, Multiple Frame Copies & Database instability.

•STP is a open standard (IEEE 802.1D)

•STP is enabled by default on all Cisco Catalyst switches

1.Selecting the Root Bridge

2.Selecting the Root Port

3.Selecting Designated port & Non Designated port

Default root bridge election : priority + Base Mac

Recommended to Select high speed Switch to be elected as Root Bridge .

1.Change priority

2.Primary / Secondary

(Config)# Spanning-tree vlan <no> hello-time <>

(Config)# Spanning-tree vlan <no> forward-time <>

(Config)# Spanning-tree vlan <no> max-age <>

Used to aggregate bandwidth between multiple L2/L3 interfaces.

Ether-Channel increases bandwidth and provides redundancy by aggregating individual links between switches.

Cisco-proprietary enhancement to Spanning Tree.

helps speed up network convergence on access ports.

Port Fast causes a port to enter the spanning-tree forwarding state immediately, bypassing the listening and learning states.

qBPDU Guard prevents loops if another switch is attached to a Portfast port.

qWhen BPDU Guard is enabled on an inter-face, it is put into an error-disabled state (basically, shut down) if a BPDU is received on the interface.

qIt can be enabled at either global configmode affects all (Portfast interfaces) or at interface mode.

Portfast does not need to be enabled for it to be configured at a specific interface.

(config)# spanning-tree portfast bpdufilter default

If a Portfast interface receives any BPDUs, it is taken out of Portfast status.

The interfaces still send some BPDUs at the link-up,

if a BPDU is received, the interface loses its Port Fast status and BPDU Filtering is disabled.

(config)# spanning-tree portfast bpduguard default

OR

(config-if)# spanning-tree bpduguard enable

# show spanning-tree summary totals

qprevents the wrong switch from becoming the Spanning Tree root.

qIf a Root Guard port receives a superior BPDU that might cause it to become a root port, the port is put into “root-inconsistent” state and does not pass traffic through it.

qIf the port stops receiving these BPDUs, it automatically re-enables itself.

Stops the loops which can occur because of unidirectional link failures.

prevents switch ports from wrongly moving from a blocking to a forwarding state when a unidirectional link exists in the network.

Do the same job as loop guard

Designed more specific for fiber ports ( can also work for UTP)

detects a unidirectional link by sending periodic hellos out to the interface.

It also uses probes, which must be acknowledged by the device on the other end of the link.

the port is automatically disabled by the switch operating system software because of an error condition that is encountered on the port.

When a port is error disabled, it is effectively shut down and no traffic is sent or received on that port.

The port LED is set to the color orange

Legacy / Cisco proprietary feature

Uplink Fast is for speeding convergence when a direct link to an upstream switch fails.

When uplinkfast is enabled, it is enabled for the entire switch and all VLANs

Backbone Fast can reduce the maximum convergence delay only from 50 to 30 seconds.

802.1w is a standards way of speeding STP convergence.

Inbuilt features of portfast, uplinkfast, backbonefast.

Path Calculation remains same as STP.

(config)#spanning-tree mode rapid-pvst

every vlan runs a separate STP instance.

Cisco proprietary. (PVST supports only ISL)

PVST+ allows interoperability between CST and PVST in Cisco switches and support the IEEE 802.1Q standard.

Provides load sharing

More overhead

Started as Cisco’s MISTP

Originally standard defined in IEEE 802.1s

allows several VLANs to be mapped to single instance of STP

reduces number of spanning-tree instances (processing overhead).

instance handles multiple VLANs that have the same Layer 2 topology.

an instance must have the same MST name and revision number

If not matches then they are considered as different instances and not the same, even if the instances contain the same vlans.

MLP combines multiple physical links into a logical bundle called an MLP bundle.

Used to aggregate multiple WAN links into one logical channel for the transport of traffic.

It enables the load-balancing of traffic from different links and allows some level of redundancy in case of a line failure on a single link.

Supports a maximum of ten member links per bundle.

Member links can be any combination of T1/E1 or fractional T1s

Initially Ethernet was only restricted to LAN ( distance limits)

Use fiber Standards support for longer distances.

Overcome both speed and Distance limits.

Service providers started using Ethernet in WAN.

PPPoE is configured as a point to point connection between two Ethernet ports.

For many cable and DSL internet connections, the ISPs inform their customers (subscribers) to set their router to receive IP address from them using username and password.

ISPs treat their subscriber's router as PPP client.

Allows virtual point to point connection over multipoint Ethernet network

PPPoE is a protocol that is widely used by ISPs to provision digital subscriber line (DSL) high speed Internet services, of which the most popular service is ADSL.

Service providers can use the same authentication server for both PPP and PPPoE sessions, resulting in a cost savings.

PPPoE uses standard methods of encryption, authentication, and compression specified by PPP.

Cisco Catalyst switches support a method of directing all traffic from a source port or source VLAN to a single port. This feature, called SPAN (for Switch Port Analyzer)

It is useful for many applications which includes monitoring traffic for compliance reasons, data collection purposes, or to support a particular application.

For example, all traffic from a voice VLAN can be delivered to a single switch port to facilitate call recording in a VoIP network. Another common use of this feature is to support intrusion detection/prevention system (IDS/IPS) security solutions.

qThe destination port for a SPAN session can be on the local switch, as in SPAN operation.

Or

qit can be a port on another switch in the network. This mode is known as Remote SPAN, or RSPAN.

q

specify that the new VLAN is an RSPAN VLAN

RSPAN VLAN, can’t be assigned to any access ports.

Requires a separate RSPAN source session to be configured

Separate RSPAN destination session to be configured.

This to check before Configuration :

Trunking

Trunk must allow remote-span Vlan

VTP (optional)

VTP if enabled ( disable for remote span Vlan)

creates a generic routing encapsulation (GRE) tunnel for all captured traffic and allows it to be extended across Layer 3 domains

supported on ASR 1000 ,Catalyst 6500, 7600, Nexus platforms.

monitoring sources include Fast Ethernet, Gigabit Ethernet, and Port-Channel interfaces.

source port can be any type of port

routed port

physical switch port

Access port

•trunk port

•EtherChannel (either one physical port or the entire port-channel interface)

•Source VLAN