ccna firewall pdf

ccna firewall pdf.15.1 EtherChannel Overview15.1.1 Introduction to EtherChannelEtherChannel (EtherChannel) is a multi-link bundling technology developed by Cisco for use between switches. The basic principle is to bundle multiple physical Ethernet links between two devices to form a logical link, forming a PortChanneD, thereby multiplying bandwidth. In addition to increasing bandwidth, EtherChannel also enables load sharing over multiple links. When one or more links fail, traffic will be transferred to other links as long as there is a working link, and the entire switching process is completed within milliseconds, thus providing redundancy and enhancing the stability and reliability of the network. A link configured with an EtherChannel is treated as a port participating in STP operations, so when STP blocks an EtherChannel link, it blocks all physical ports under the entire EtherChannel. In the EtherChannel, load sharing of traffic across links can be configured based on source IP address, destination IP address, source MAC address, destination MAC address, combination of source IP address and destination IP address, combination of source MAC address and destination MAC address, and so on.EtherChannel can bundle Access ports, Trunk ports, and Layer 3 ports. An EtherChannel can bundle up to 16 ports, of which up to 8 can be active. The number of EtherChannels supported varies by switch type. When configuring an EtherChannel, the configuration (such as Trunk encapsulation, rate, and duplex mode) must be the same for all ports in the same group, so Trunk ports and Access ports cannot be bundled together. .15.1.2 PAgP and LACP Negotiation LawsEtherChannel can be configured manually or negotiated automatically. There are currently two EtherChannel negotiation protocols: PortAggregationProtocol (PAgP) and LinkAggregationControlProtocol (LACP), PAgP is a Cisco private protocol, and LACP is an international standard. These two protocols each have different modes of operation, and different combinations of modes will have different negotiation results. The PAgP negotiation pattern is shown in Table 15.1, and the LACP negotiation pattern is shown in Table 15-2..252.Cisco Networking Lab CCNA Lab Guide (Release 2) Table 15-1 PAgP Negotiation LawON Desirable AutoON 7 X XDesirable (Desired) X V V