CCNP CCIE Complete

Configuring the VTP Version There are two versions of VTP that are configurable on Cisco switches. Version 1 is the default VTP version on all switches and is typically used. No VTP version configuration is needed if you will be ... [full story]

2950 and 3550 Series The 2950 switches support the same options but with different commands, as in the next example. The 2950 series supports only IEEE 802.1Q VLANs, whereas the 3550 support ISL as well: Terry_2950(config-if)#switchport trunk ? allowed Set ... [full story]

4000 Switch To configure a trunk on a 4000 series switch, use the set trunk command, and on the IOS-based switch, use the trunk on command: Terry_4000> (enable) set trunk 2/12 ? Usage: set trunk <mod_num/port_num> [on|off|desirable|auto|nonegotiate] [vlans] [trunk_type] (vlans ... [full story]

Configuring Trunk Ports This section shows you how to configure trunk links on the 4000 series and the 2950/3550 series IOS-based switches. [full story]

Trunking Trunk links are point-to-point, 100Mbps, or 1000Mbps links between two switches, between a switch and a router, or between a switch and a server. Trunk links carry the traffic of multiple VLANs, from 1 to 1005 at a time. ... [full story]

Standard for Virtual Bridged Local Area Networks (IEEE 802.1Q) Unlike ISL, which uses an external tagging process and encapsulates a frame with a new ISL encapsulation, 802.1Q uses an internal tagging process by modifying the existing internal Ethernet frame. To ... [full story]

Inter-Switch Link Protocol (ISL) Inter-Switch Link Protocol (ISL) is a way of explicitly tagging VLAN information onto an Ethernet frame. This tagging information enables VLANs to be multiplexed over a trunk link through an external encapsulation method. By running ISL, ... [full story]

VLAN Identification Methods To keep track of frames traversing a switch fabric, VLAN identification is used to identify which frames belong to which VLAN. There are multiple trunking methods: Inter-Switch Link (ISL) Proprietary to Cisco switches, ISL is used for ... [full story]

Frame Tagging The switch in an internetwork needs a way to keep track of users and frames as they travel the switch fabric and VLANs. Frame identification, called frame tagging, uniquely assigns a userdefined ID to each frame. This is ... [full story]

Identifying VLANs VLANs can span multiple connected switches, which (as we stated earlier) Cisco calls a switch fabric. Switches within the switch fabric must keep track of frames as they are received on the switch ports, and they must keep ... [full story]

Catalyst 2950 and 3550 Series To configure VLANs on an IOS-based switch, first you need to enter the VLAN database. This mode is entered by typing the command vlan database. This command changes the prompt, as can be seen from ... [full story]

Catalyst 4000 Series To configure VLANs on a Catalyst 4000 switch, use the set vlan vlan# name vlan_name command. Then, after your VLANs are configured, assign the ports to each VLAN: Terry_4000> (enable) set vlan 2 name Sales Vlan 2 ... [full story]

Configuring Static VLANs For the Switching exam, Cisco is primarily interested in static VLAN configuration. We’ll show you how to configure VLANs on a Catalyst 4000 switch and on a range of Catalyst IOS-based switches. It is important to understand ... [full story]

Dynamic VLANs If the administrator wants to do a little more work up front and add all devices’ hardware addresses to a database, hosts in an internetwork can be assigned VLAN assignments dynamically. By using intelligent management software, you can ... [full story]

Clearing VLANs from Trunk Links As demonstrated in the preceding sections, all VLANs are configured on a trunk link unless cleared by an administrator. If you do not want a trunk link to carry VLAN information because you want to ... [full story]

4000 Series The command to clear a VLAN from a trunk link is clear trunk slot/port vlans. Here is an example: Terry_4000> (enable) clear trunk 2/12 5-1005 Removing Vlan(s) 5-1005 from allowed list. Port 1/2 allowed vlans modified to 1-4 [full story]

Configuring VTP There are several options that you need to be aware of before attempting to configure the VTP domain: 1. Consider the version number of the VTP you will run. 2. Decide if the switch is going to be ... [full story]

Subset Advertisements The subset advertisements contain specific information about a VLAN. After an administrator adds, deletes, or renames a VLAN, the switches are notified that they are about to receive a VLAN update on their trunk links via the VLAN-info ... [full story]

Management domain name The switch that receives this advertisement must have the name that is in this field, or the update is ignored. [full story]

VTP advertisement content Version Code Rsvd Mgmt D Len Management domain name Version code follows mgmt D Len Config revision number Management domain name Client Advertisement Request Summary Advertisement Start value Updater identity MD5 Updater timestamp Version Code Seq num ... [full story]

VTP Advertisements After the different types of VTP switches are defined, the switches can start advertising VTP information between them. VTP switches advertise information they know about only on their trunk ports. They advertise the following:  Management domain name ... [full story]

Transparent VTP transparent switches do not participate in the VTP domain, but they still receive and forward VTP advertisements through the configured trunk links. However, for a transparent switch to advertise the VLAN information out the configured trunk links, VTP ... [full story]

Client VTP clients receive information from VTP servers and send and receive updates, but they cannot make any changes to the VTP configuration as long as they are clients. No ports on a client switch can be added to a ... [full story]

Server VTP server mode is the default for all Catalyst switches. You need at least one server in your VTP domain to propagate VLAN information throughout the domain. The following must be completed within server mode:  Create, add, or ... [full story]

The Threat of High Revision Numbers Many organizations have discovered the need for physical security when a device with only VLAN 1 but a high configuration revision number is added to the network. If a switch is a part of ... [full story]

VTP Modes of Operation There are three modes of operation within a VTP domain: server, client, and transparent. Figure 14.4 shows the three VTP modes. [full story]

Using VLAN Trunk Protocol (VTP) VLAN Trunk Protocol (VTP) was created by Cisco to manage all the configured VLANs across a switched internetwork and to maintain consistency throughout the network. VTP enables an administrator to add, delete, and rename VLANs. ... [full story]

Verifying Trunk Links On the 4000 series, you can verify your trunk ports using the show trunk command. If you have more than one port trunking and want to see statistics on only one trunk port, you can use the ... [full story]

2950 and 3550 Series Switches The command switchport trunk allowed vlan remove vlan-list is used to limit which VLANs can use a particular trunk: Terry_2950(config)# interface fa 0/10 Terry_2950(config-if)# switchport trunk allowed vlan remove 2-10,12,15 Use a hyphen to show ... [full story]

Static VLANs In a static VLAN , the administrator creates a VLAN and then assigns switch ports to it. The association does not change until the administrator changes the port assignment. This is the typical way of creating VLANs, and ... [full story]

Assigning VLAN Memberships After your VLANs are created, you need to assign switch ports to them. There are two types of VLAN port configurations: static and dynamic. A static VLAN requires less work initially but is more difficult for an ... [full story]

Local VLANs Unlike an end-to-end VLAN, a local VLAN is configured by physical location and not by function, project, department, and so on. Local VLANs are used in corporations that have centralized server and mainframe blocks because end-to-end VLANs are ... [full story]