ccna chapter 4 pdf

ccna chapter 4 pdf.Type:802.1Qvirtual LAN (0x8100) S 802.IQVirtualLAN, PRI: 0,CFI: 0,ID: 2000 ................................. = Priority:BestEffort(default)(0) ... .0.................................. = CFI:canonical(0) .... 00000000 0010 = ID: 2Type: EP (0x080.)Figure 8-1 IEEE 802.lq frame formatThe re-encapsulation of ISL or the insertion of IEEE 802.1q tags on the Trunk link will directly cause the frame header to become larger, thus affecting the link transmission efficiency. The frames from the Native VLAN will be transmitted in the original frame format without re-encapsulation. Obviously, the native VLANs specified on both ends of the trunk link must be the same, otherwise it may cause data frames to be propagated from one VLAN to the other, and it may also cause problems such as CDP message errors and switching loops. However, intrinsic VLANs may lead to VLAN hopping attacks, so in practice, the intrinsic VLAN is usually configured as a non-existent VLAN, i.e. all VLAN data frames passing through the Trunk link are inserted with tags.8.2.2 VoiceVLANIP telephony is commonly used in modern networks. An IP phone can be thought of as a switch with 3 ports built in. To ensure IP voice quality, a separate VLAN is usually used to carry IP voice traffic so that the link between the IP phone and the switch onChapter 8 VLANs, Trunk, and Inter-VLAN Routing .105 .Traffic exists for both the voice VLAN and the data VLAN (sent by the computer). it would seem that this link should be configured as a Trunk link. However. the ports on the switch are usually configured in Access mode for security and other reasons. However, Access mode ports will not receive data frames that are encapsulated in Trunk. Voice VLAN can resolve this conflict. On the switch.106.Cisco Networking Lab CCNA Lab Guide (Release 2) With a Voice VLAN configured on a port, the IP phone trunk-encapsulates the voice data (tagged with the ID of the Voice VLAN)