CNNA3-Chapter 3: Part II pot

CCNA3-1 Chapter 3-2 Chapter 3 Chapter 3 Virtual Local Area Networks Virtual Local Area Networks (VLANs) (VLANs) Part II Part II CCNA3-2 Chapter 3-2 Virtual Local Area Networks Virtual Local Area Networks VLAN Trunking VLAN Trunking CCNA3-3 Chapter 3-2 VLAN Trunking VLAN Trunking • The concept of The concept of trunking trunking began with the telephone industry. began with the telephone industry. • Multiple calls were moved between customers and central Multiple calls were moved between customers and central offices or between the offices themselves over a single offices or between the offices themselves over a single physical connection. physical connection. CCNA3-4 Chapter 3-2 VLAN Trunking VLAN Trunking • The same principle was applied to data communications to The same principle was applied to data communications to make better use of the communication line. make better use of the communication line. • Additional advantages and cost savings were gained by Additional advantages and cost savings were gained by using the same line for voice communications. using the same line for voice communications. 24 Channel T1 Line with Data and Voice CCNA3-5 Chapter 3-2 VLAN Trunking VLAN Trunking • The same principle of trunking is applied to network switching The same principle of trunking is applied to network switching technologies. technologies. • A trunk A trunk is a is a physical and logical physical and logical connection between two connection between two switches across which network traffic travels. switches across which network traffic travels. No trunk No trunk No trunk No trunk Trunk Trunk Trunk Trunk CCNA3-6 Chapter 3-2 VLAN Trunking VLAN Trunking • It is also important to It is also important to realize that a trunk link realize that a trunk link does not belong does not belong to a to a specific VLAN. specific VLAN. • The responsibility of a The responsibility of a trunk link is to act as a trunk link is to act as a conduit conduit for VLANs. for VLANs. • Between Between switches switches and and routers routers . . • Between Between switches switches and and switches switches . . CCNA3-7 Chapter 3-2 VLAN Trunks VLAN Trunks • What problem does it solve? What problem does it solve? Network 172.17.10.0/24 Network 172.17.10.0/24 Network 172.17.10.0/24 Network 172.17.10.0/24 Network 172.17.20.0/24 Network 172.17.20.0/24 Network 172.17.20.0/24 Network 172.17.20.0/24 Network 172.17.99.0/24 Network 172.17.99.0/24 Network 172.17.99.0/24 Network 172.17.99.0/24 Network 172.17.30.0/24 Network 172.17.30.0/24 Network 172.17.30.0/24 Network 172.17.30.0/24 CCNA3-8 Chapter 3-2 IEEE 802.1Q Frame Tagging IEEE 802.1Q Frame Tagging • Remember that switches are Layer 2 devices. Remember that switches are Layer 2 devices. • Only use the Ethernet frame header information. Only use the Ethernet frame header information. • Frame header does not contain information about VLAN Frame header does not contain information about VLAN membership. membership. • VLAN membership (i.e. VLAN ID or VLAN Number) must be VLAN membership (i.e. VLAN ID or VLAN Number) must be identified for each frame that is transferred over the trunk. identified for each frame that is transferred over the trunk. • The process is called The process is called 802.1Q VLAN Tagging. 802.1Q VLAN Tagging. CCNA3-9 Chapter 3-2 IEEE 802.1Q Frame Tagging IEEE 802.1Q Frame Tagging 6 6 2 1500 4 Destination Address Source Address Type / Length Data Max of 1500 Bytes FCS 6 6 2 2 2 1500 4 Destination Address Source Address 802.1Q Tag Type/ Length Data Max of 1500 Bytes New FCS 8100 Tag Length 1518 Bytes Length 1518 Bytes Length 1518 Bytes Length 1518 Bytes Length 1522 Bytes Length 1522 Bytes Length 1522 Bytes Length 1522 Bytes CCNA3-10 Chapter 3-2 6 6 2 2 2 1500 4 Destination Address Source Address 802.1Q Tag Type/ Length Data Max of 1500 Bytes New FCS 8100 Tag IEEE 802.1Q Frame Tagging IEEE 802.1Q Frame Tagging Length 1522 Bytes Length 1522 Bytes Length 1522 Bytes Length 1522 Bytes 3 Bits 3 Bits 1 Bit 1 Bit 12 Bits 12 Bits User User Priority Priority CFI CFI VLAN ID VLAN ID Canonical Format Identifier Canonical Format Identifier Canonical Format Identifier Canonical Format Identifier . 3 Virtual Local Area Networks Virtual Local Area Networks (VLANs) (VLANs) Part II Part II CCNA3-2 Chapter 3-2 Virtual Local Area Networks Virtual Local Area