network cisco ccna gns3 certification arteq

network cisco ccna gns3 certification arteq
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Monday, December 24, 2012

tcam info...


and this:

note there is no allocation for pbr...

dlsw1#sh sdm prefer                                                               
 The current template is "desktop IPv4 and IPv6 default" template.                
 The selected template optimizes the resources in                                 
 the switch to support this level of features for                                 
 8 routed interfaces and 1024 VLANs.                                              
  number of unicast mac addresses:                  2K                            
  number of IPv4 IGMP groups + multicast routes:    1K                            
  number of IPv4 unicast routes:                    3K                            
  number of directly-connected IPv4 hosts:        2K                            
  number of indirect IPv4 routes:                 1K                            
  number of IPv6 multicast groups:                  1.125k                        
  number of directly-connected IPv6 addresses:      2K                            
  number of indirect IPv6 unicast routes:           1K                            
  number of IPv4 policy based routing aces:         0                             
  number of IPv4/MAC qos aces:                      0.5K                          
  number of IPv4/MAC security aces:                 1K                            
  number of IPv6 policy based routing aces:         0                             
  number of IPv6 qos aces:                          0.625k                        
  number of IPv6 security aces:                     0.5K


looks like ipv4-and-ipv6 routing may be the best choice... at least a little is spared for pbr...

and from wiki:

Content-addressable memory is often used in computer networking devices. For example, when a network switch receives a data frame from one of its ports, it updates an internal table with the frame's source MAC address and the port it was received on. It then looks up the destination MAC address in the table to determine what port the frame needs to be forwarded to, and sends it out on that port. The MAC address table is usually implemented with a binary CAM so the destination port can be found very quickly, reducing the switch's latency.

Ternary CAMs are often used in network routers, where each address has two parts: the network address, which can vary in size depending on the subnet configuration, and the host address, which occupies the remaining bits. Each subnet has a network mask that specifies which bits of the address are the network address and which bits are the host address. Routing is done by consulting a routing table maintained by the router which contains each known destination network address, the associated network mask, and the information needed to route packets to that destination. Without CAM, the router compares the destination address of the packet to be routed with each entry in the routing table, performing a logical AND with the network mask and comparing it with the network address. If they are equal, the corresponding routing information is used to forward the packet. Using a ternary CAM for the routing table makes the lookup process very efficient. The addresses are stored using "don't care" for the host part of the address, so looking up the destination address in the CAM immediately retrieves the correct routing entry; both the masking and comparison are done by the CAM hardware.

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