2023-04-24
Last updated
Last updated
Switching happens inside a switch.
Routing occurs between routers. They exchange information to decide which next router the packet should go.
Router is often called L3 switch. Switch often refers to all kinds of switches. Specifically, it refers to L2 switch.
Layer 3 (Network layer) protocol.
IPv4 -> 32bit address. 4G unique addresses. IPv6 -> 128 bit address. 4G^4 unique addresses.
type of service - ECN and ?
length is 16bit -> the maximum length of datagram is 64K bytes.
typically 1500 bytes or less. it is usually confined by ethernet MTU(max transmit unit) size.
fragmentation?
Time to live : remaining max hops.
upper layer protocol : TCP is 6
header checksum is only the checksum of the header.
/24 address - > CIDR-ized notation method. means high order 1 addresses.
Dynamic Host Configuration Protocol
temporarily assigns ip addresss of new client in subnet. "leases"
DHCP scenario
DHCP discover (from client) Broadcast to find if there is available DHCP server in this subnet. local broadcast (255.255.255.255:67)
DHCP offer
DHCP Request
DHCP ack
DHCP another role
return address of gateway of this subnet
ISP can allocate in 8 blocks.
