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5.5 Describe network programmability in enterprise network architecture Cisco Express Forwarding (CEF) - Allows routers to send bits. Data plane vs control plane. Does not refer to the control plane for decision. Decisions are made based off arp table. Turbocharger for routing. 5.5a Function of a controller - A controller or SDN controller can centralize the control of the network devices. It can vary from controlling all plane functions to monitoring and being aware of the ongoing work on the distribution plane. 5.5b Separation of control plane and data plane - A data plane refers to the actual processing of the data, whether it be packets, frames or bits. Anything involving receiving the data, processing or forwarding it relates to the data plane. - Routing protocols (OSPF, EIGRP, RIP, BGP) - IPv4 ARP - IPv6 NDP - Switch MAC learning - STP - A control plane is any action that controls the data plane. For example, creating tables which are used by the data plane like the IP routing table, IP ARP table, a switch MAC address table, etc. By adding, removing and changing entries to the
tables used by the data plane, the control plane processes control what the data plane does. - SSH - FTP
5.5c Northbound and Southbound APIs - API (Application Programing Interface) - A method for one program to exchange data with another application. - An interface to an application program. - Programs process data so and API lets two programs exchange data. - While a program exists as a document, an API exists as usable code- functions, variables and data structures, that can be used by one program to communicate and copy structured data between programs across a network. - NBI: - SBI: - An interface between a program (controller) and a program (on the networking device) that lets two programs communicate, with the controller allowed to program the data plane forwarding tables of the networking device.
5.6 Troubleshoot basic Layer 3 end-to-end connectivity issues
Proxy ARP: Hosts do not require a default gateway configuration when proxy Address Resolution Protocol (ARP) is configured. - Enables hosts to communicate with hosts on remote networks. - Increase the amount of ARP traffic on a network segment. Less secure than traditional ARP configuration. - When configured, it is possible for hosts on a remote network to spoof hosts on the local network. - Host ARP tables are larger when proxy ARP is configured.
Show Version: This command will display the IOS version, the configuration setting and the amount of memory installed. In addition, it will display system hardware configuration information, the names and sources of boot images on a router, and many other pieces of information. (0x2102 is default, 0x2142 ignores the startup configuration on the next reload)
Difference between stateful DHCP with IPv6 and IPv4 - In an IPv6 environment, the DHCP server does not provide the default gateway. - It is provided by the neighbor discovery
process built in the protocol.
- IPv6 stateful DHCP will provide subnet mask information, lease duration information and DNS information as required.