Files
uni/third/semester1/CT3531: Network & Data Communications II/papers/exam_papers_answers.txt

46 lines
1.6 KiB
Plaintext

Question 1.
a) (i) 10.16.0.0/16
4 bits needed for subnetting.
Leaves 12 bits for host addressing.
2^12 = 4096
Subnet mask will be /20 or 255.255.240.0 (don't need to know dotted decimal notation)
(ii) Will never ask the last one (again).
First subnet: 10.16.10.0./20
Hosts: 10.16.0.1 --> 10.16.15.254
Broadcast: 10.16.15.255
Second subnet: starts from where the first left off
Hosts: 10.16.16.1 --> 10.16.31.254
Broadcast: 10.16.31.255
(iii) 10.16.0.0/13
which represents everything form 10.16.0.0 --> 10.23.0.0
b)
- a good answer will be about page
- write legibly
- no competitor for DNS.
- don't expect us to know competitors for GNS3
- IXPs are well covered in the notes.
- why do IXPs exist?
- to keep internet routing as efficient and local as possible
- what do they do?
Question 2.
a) Reasons to use VLANs:
- keep traffic separate
- security
- limit broadcast traffic
VLAN 1 is usually reserved as the "Native VLAN"
VLAN ID is 12 bits so maximum is 4096.
Any valid VLAN ID and subnet is acceptable
b) `e0` would be dot1q because it is a trunk port: tags traffic for VLANs
`e1` would be dot1q because it is a trunk port: tags traffic for VLANs
`e2` is an access port for the Support VLAN
802.1q tags ethernet headers to add the VLAN ID so the packet goes to the correct VLAN.
Also have 3 bits which define priority for the packet.