agg-ain...

notice the aggregated bandwidth upon showing the channel...


dsw1#sh int po1
Port-channel1 is up, line protocol is up (connected)
  Hardware is EtherChannel, address is 000f.8ffe.0980 (bia 000f.8ffe.0980)
  Internet address is 10.1.4.13/30
  MTU 1500 bytes, BW 200000 Kbit, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, media type is 10/100BaseTX

can't get that with spanning tree in effect, but...
there are two trunk links per 2950 switch from each dsw as in the diagram... the channel is conspicuously missing from the out put of spanning tree...



VLAN0010
  Spanning tree enabled protocol ieee
  Root ID    Priority    20490
             Address     000f.8ffe.0980
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    20490  (priority 20480 sys-id-ext 10)
             Address     000f.8ffe.0980
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Fa0/3               Desg FWD 19        128.3    P2p
Fa0/4               Desg FWD 19        128.4    P2p


and in the output of sh vlan brief the channel (fa0/1 - 2) as well as both fa0/3 and 4 are all missing... they're kinda busy...


dsw1#sh vlan brie

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
1    default                          active    Gi0/1, Gi0/2
10   data                             active    Fa0/6, Fa0/7, Fa0/8, Fa0/9
                                                Fa0/10, Fa0/11, Fa0/12, Fa0/13
                                                Fa0/14, Fa0/15, Fa0/16, Fa0/17
                                                Fa0/18, Fa0/19, Fa0/20, Fa0/21
                                                Fa0/22, Fa0/23, Fa0/24

the necessary evil...

ipv6

larger address space

128 bits binary, 32 hex digits
enhanced reachability and flexibility
prefix aggregation for routing
multihoming
autoconfiguration that includes hardware addresses
plug and play
doesn't need public to private translation
address renumbering and modification made simple

simpler header

routing efficiency and scalability
no broadcasts, no broadcast storms
no checksums
simpler header extension
flow labels;  no need to open transport packet to identify traffic flows

mobility, security

mobile ip and ipsec standards functionality built in
ipsec enabled on every node

incorporation with ipv4

dual stack; ipv6 and ipv4 on the same INTERFACE
tunneling; if you can't stack, tunnel
NAT translation between ipv6 and ipv4 in IOS since 12.3(2)T

32 hex numbers in 8 quartets of 4 hex digits separated by colons
   omit leading zeros
   a single instance of consecutive quartets of zero's can be represented by a double colon (quartet = 1 set of
   4 digits hex times 8 for total

a prefix equals a block of consecutive ipv6 addresses and is represented in routing tables
prefix values need to fall on quartet boundaries or include all values in the last quartet