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Flashcards in SDN Deck (8)
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1
Q

what are the functions of data plane

A

local, per-router function

determines how datagram arriving on router input port is forwarded to router output port

forwarding function

2
Q

what are the functions of control plane

A

network-wide logic

determines how datagram is routed among routers along end-end path from source host to destination host

3
Q

what is a SDN?

A

A network in which the control plane is physically separate from the data plane,
and
A single (logically centralized) control plane controls several forwarding devices.

The controller interacts with a control agent (CA) in each of the routers via a well-defined protocol to configure and manage that router’s flow table

4
Q

what is management plane?

A

configuring and tuning the network – Traffic engineering, ACL configuration, device provisioning, …

5
Q

what do you mean logically centralized?

A

By “logically centralized” control we mean that the routing control service is accessed as if it were a single central service point, even though the service is likely to be implemented via multiple servers for fault-tolerance, and performance scalability reasons

6
Q

what are the headers in open flow?

A

Pattern: match values in packet header fields

Actions: for matched packet: drop, forward, modify, matched packet or send matched packet to controller

Priority: disambiguate overlapping patterns

Counters: #bytes and #packets

7
Q

Why a logically centralized control plane?

A

easier network management: avoid router misconfigurations, greater flexibility of traffic flows
table-based forwarding (recall OpenFlow API) allows “programming” routers

centralized “programming” easier: compute tables centrally and distribute

distributed “programming: more difficult: compute tables as result of distributed algorithm (protocol) implemented in each and every router

open (non-proprietary) implementation of control plane

8
Q

what if network operator wants u-to-z traffic to flow along uvwz, x-to-z traffic to flow xwyz?

A

need to define link weights so traffic routing algorithm computes routes accordingly