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@Layer2
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btw 2 devices inside own NW or LAN
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@Layer3
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btw 2 NWs or 2 subnets
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Notation
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dotted-decimal | 4x8bits = 32bits
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||
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Subnet mask
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defines NW proportion (1=NW, 0=host)
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||
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Classes
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classful mask = default subnet mask
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||
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- Class A
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1-126
|
255.0.0.0
|
/8
|
|
- Class B
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128-191
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255.255.0.0
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/16
|
|
- Class C
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192-223
|
255.255.255.0
|
/24
|
|
- Class D
|
224-239
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n/a
|
n/a
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IP Types
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|||
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- Routable
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Public IPs purchased and used by ISP
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||
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- Private
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non routable
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||
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A
|
10.0.0.0/8
|
10.255.255.255/8
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|
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B
|
172.16.0.0/16
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172.31.255.255/16
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|
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C
|
192.168.0.0/24
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192.168.255.255/24
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|
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- Specialized
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127.x.x.x
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loopback adress for local testing
|
|
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- Automatic
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APIPA
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assigned by OS if DHCP u/s
|
|
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- Virtual
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VIP(A)
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not correlating to any NIC
|
|
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ex @L7: loadbalancer, failover
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|||
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ex @L3: HSRP (Hot StandBy Routing Prot.)
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|||
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Unicast
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single destination
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|
Multicast
|
multi-specific destination
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Broadcast
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all devices on a network
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Static
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simple, time-consuming, prone to error, hard to setup in large scale
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Dynamic
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quick, easy, scalable
|
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Content
|
IP adress, subnet mask, default GW, DNS server (or WINS)
|
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TTL
|
time for which an IP is leased to a host. After, IP is given back to IP pool
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APIPA
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IP self-assigned in case of DHCP unavailable, from the network 169.254.0.0/16
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ZeroConf
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idem but more recent, using mDNS and DNS-SD
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Purpose
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scaling NW according to its scope of use, to control bandwidth
|
||||
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How
|
borrow bits from original host portion and add them to the NW portion
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||||
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Calculation
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|||||
|
IP
|
10.
|
180.
|
122.
|
244
|
/13
|
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Mask
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255.
|
248.
|
0.
|
0
|
|
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256-248 = 8 hots/subnet | 180%8 = 4 | 180-4 = 176
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|||||
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Subnet
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10.
|
176.
|
0.
|
0
|
|
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the next subnet is 176+8=184
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|||||
|
Brdcst
|
10.
|
183.
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255.
|
255
|
|
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1st IP
|
10.
|
176.
|
0.
|
1
|
|
|
Last IP
|
10.
|
183.
|
255.
|
254
|
|
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