cisco ccna kniha pdf

cisco ccna kniha pdf.Subinterface Types As described in Chapter 15, there are two types of subinterfaces: point-to-point and multipoint. Multipoint subinterfaces (subinterfaces that terminate multiple VCs) are ideal for use in a fully meshed network. If the WAN is using a full mesh topology, all devices can be placed in a single subnet, so only one network number is required to address the devices. However, multipoint subinterfaces are less suitable for partial mesh networks because they pose problems for routing protocols that use horizontal segmentation.If you are concerned about the addressing needs of point-to-point subinterfaces, you can use the interface subconfiguration mode command ip unnumberedo This command borrows the IP address of another active interface on the router, allowing you to eliminate the need to assign subnets to connections. Most network administrators do not use this command because it has its problems, but this is not part of the discussion in this book.Point-to-point subinterfaces are best used in partially meshed environments and in environments that require simulated leased-line connections. Point-to-point subinterfaces are used to overcome the problems associated with routing protocols that use horizontal segmentation, but like multipoint subinterfaces, point-to-point subinterfaces have their problems, the biggest of which is that each point-to-point subinterface requires a separate network or subnet number. If there are 200 sub-interfaces on the serial interface, 200 subnets are required to meet the addressing requirements.The point-to-point subinterfaces emulate leased-line circuits and are used to solve horizontal segmentation problems. Each sub-interface requires a separate IP address/subnet.Creating SubinterfacesVideo 25.09.A multimedia demonstration of creating a subinterface on a router is included in the digital resources that accompany this book.Chapter 25 Frame Relay 707To create a subinterface, use the following syntax.Router(config)# interface serial /]port_#.subinterface_# {point-to-point | multipoint}