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August 2012

IPv6 Routing

1. Enable IPv6 Routing To enable IPv6 routing, use: This will enable the router to send RAs unsolicited or in response to RS messages. 2. Static Routing To see the routing table, use: 3. RIP for IPv6 RIP for IPv6, aka RIPng, works just like RIPv2 for IPv4. It sends …

IPv6-101

1. IPv6 Packet Format The IPv6 header has a fixed format (as opposed to the variable format of IPv4) of 40 Bytes. Version – 4 bits – always set to the value 6 Traffic Class – 8 bits – 6 most significat bits are used for DSCP, 2 least significant bits are used …

Route Redistribution

1. Route Redistribution You can redistribute routes from one routing process to another using the redistribute command inside the destination routing process: When a routing protocol starts, it automatically redistributes connected routes that are matched by the network command. This also happens for static routes that point to an interface …

Routing over Frame Relay

1. Topologies 1.1 Full Mesh The simplest Frame Relay topology is the Full Mesh topology, where each router has a dedicated virtual circuit to another router. Unfortunately this design is rarely found in real life because each additional circuit costs. Of course, having so many circuits available makes it easy …

Bridging on a router

1. Bridging Transparent Bridging is the default operational mode of switches. They bridge between interfaces and switch between them without modifying any data in the frames. Routing is the default operation mode of routers. They route between interfaces, and when doing this they modify the packets (Source and Destination MAC, …

Switch ACLs

1. Port ACLs Can only be applied on physical L2 interfaces on a switch (not on etherchannels). They can only be applied on the inbound direction. A port ACL can be either a Standard ACL, an Extended ACL or an Extended MAC ACL. Only one standard or extended ACL and …

802.1x

1. Device Roles Client – aka “The Supplicant” – The client device that connects to the network. It must rung an 802.1x compliant software Authentication Server – performs the actual authentication based on the client credentails. Switch – aka “The authenticator” – acts as a proxy between the Client and …

DHCP Snooping and DAI

1. DHCP Snooping DHCP snooping can prevent unauthorized DHCP servers to reply to DHCP requests. A switch can define interfaces as trusted or untrusted. A trusted interface is where a DHCP server should be connected. On such interfaces, DHCP server messages are allowed. On all other untrusted ports, DHCP server …

EtherChannel 101

An etherchannel is a logical port that consists of multiple links bundled into a single logical link. To have a working etherchannel you must use static config or a negotiation protocol (LACP or PAgP). All ports in an EtherChannel must operate at the same speed and duplex. When an EtherChannel …

VLANs

1. Supported VLANs Supported VLANs: 1-4094 Optional parameters: To verify: 1.1 Normal Range vs Extended Range Normal Range VLANs: 1-1005* – Supported by VTP v1,v2,v3 in all modes. Extended Range VLANs: 1006-4094 – Only supported in Transparent mode by VTPv1 and v2, and in all modes by VTP v3. * …