"Federated learning: out of reach no matter how close",Oleksandr Lapshyn
Et3003 sem2-1314-10 vlans
1. VLAN
Virtual Local Area Networks
Computer Networks
Tutun Juhana
Telecommunication Engineering
School of Electrical Engineering & Informatics
Institut Teknologi Bandung
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Source: Hands-On Networking, From Theory to Practice, by MARIA LUISA MERANI,
MAURIZIO CASONI, ALTER CERRONI, Cambridge Uni.Press, 2009
2. • Powerful and flexible solutions to build
switched environments
• The evident advantage is to allow the
logical grouping of stations into disjoint
broadcast domains, regardless of their
physical location
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5. VLAN classification
• Static VLANs
– The network administrator assigns switch
ports to a specific VLAN
– That’s why static VLANs sometimes referred
to as port-based VLANs
• Dynamic VLANs
– The criterion leading the VLAN membership is
the station address, either layer-2 (MAC
address), or layer-3 (network address)
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8. VLAN on a single switch
• Switch configuration encompasses two steps
1. The creation of two VLANs with their respective
VLAN identifier, VID
2. The assignment of the desired switch ports to each
VLAN 8
9. VLAN on multiple switches
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A switch-to-switch connection allows intra-VLAN communication
The two points worthy of mention are:
1. Frames originating within both VLANs need to traverse the connection between
the two switches;
2. The two switches will have to share some type of VLAN database (no matter
whether a static or dynamic VLAN configuration is adopted)
such a brute force
approach would
require each switch
to know the
assignment of the
other switch ports for
the shared VLAN
10. 10
Complex VLAN databases and
the consequent burdensome
switch forwarding operations are
not the correct answer
11. The tag
Tagging to the
rescue
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• The tag solution is partly provided
by the IEEE 802.1Q standard
• Each frame carry a tag the tag
contain a VID the switches
exclusively rely on VIDs for inter-
switch forwarding
