N10-009
Objective 1.4
Chapter 2

Network Traffic Types:
How Data Finds Its Audience

Unicast, Multicast, Anycast, Broadcast — four ways to deliver packets to their destinations. Understanding these is foundational to subnetting, IPv6, routing, and network troubleshooting.

Objective 1.4 — Explain the characteristics of network traffic types.
You need to identify each type by behavior, address range, and use case on the exam.
8 Slides N10-009 Obj 1.4 Chapter 2
N10-009
Traffic Types
Unicast

One to One

Traffic Flow
SRC 192.168.1.10 DST 10.0.0.5 HOST HOST
SenderOne source host
TargetOne specific destination host
IP RangeAny standard unicast IP address

Examples

  • HTTP/HTTPS request to a web server
  • SSH session to a remote host
  • Email delivery (SMTP client to server)
  • File transfer (FTP, SCP)

Addressing

Example flow:

192.168.1.10 → 10.0.0.5

Any valid IP destination address that belongs to a single host.

Key Point
Most network traffic is unicast. When you browse a website, open a Zoom call, or send a file — every one of those packets uses unicast addressing.
N10-009
Traffic Types
Broadcast

One to All

Traffic Flow
SRC 192.168.1.10 HOST HOST HOST HOST

Addresses

Limited255.255.255.255
Directed192.168.1.255 (subnet /24)
MACFF:FF:FF:FF:FF:FF

Examples

  • ARP Request — "Who has 10.0.0.1? Tell 10.0.0.50"
  • DHCP Discover — "Any DHCP servers out there?"
  • NetBIOS name resolution
  • Routing protocol announcements (some)
Key Point
Broadcasts do not cross routers. Every router interface is a broadcast domain boundary. This is why each VLAN or subnet is its own broadcast domain.
Exam Tip
IPv6 has NO broadcast. It replaces all broadcast functions with multicast. This is a high-frequency exam question.
N10-009
Traffic Types
Multicast

One to Many — Subscribers Only

Traffic Flow
SRC 224.0.0.5 SUB joined SUB joined SUB joined NS NS NS = not subscribed
IP Range224.0.0.0 – 239.255.255.255
ClassClass D
ProtocolIGMP manages group membership

Key Multicast Addresses

Address Used For
224.0.0.1All hosts on segment
224.0.0.2All routers on segment
224.0.0.5All OSPF routers
224.0.0.6OSPF DR/BDR routers
224.0.0.9RIPv2 routers

Examples

  • IPTV / video streaming
  • OSPF routing updates
  • Windows deployment (SCCM/WDS)
  • Online gaming state sync
Key Point
The sender transmits once. The network replicates to all subscribers. Non-subscribers receive nothing. This is far more efficient than broadcast for group delivery.
N10-009
Traffic Types
Anycast

One to Nearest

Traffic Flow — Same IP, Nearest Instance Wins
CLIENT queries NEAREST 198.41.0.4 WINS INST 198.41.0.4 INST 198.41.0.4 INST All share same IP
HowMultiple servers share one IP. BGP routing selects the topologically closest.
MetricRouting metric (hop count, latency, BGP path attributes)

Real-World Examples

  • DNS Root Servers — 13 letter labels, hundreds of physical servers worldwide, all sharing the same IP via anycast
  • CDN Edge Servers — Cloudflare, Akamai route you to the nearest PoP
  • IPv6 Anycast — Natively defined in the IPv6 spec for service redundancy
  • DDoS mitigation services
Key Point
All 13 DNS root server letters use anycast. When you query a.root-servers.net, you do not hit a single server in the US — you hit the nearest physical instance of "A root" in your region.
Exam Tip
Anycast is the newest concept on the N10-009. The key idea: same IP configured on multiple servers, routing directs traffic to the nearest one. It is about routing topology, not a new protocol.
N10-009
Traffic Types

All Four — Side by Side

Attribute Unicast Broadcast Multicast Anycast
Targets 1 specific host All hosts on segment Group of subscribers Nearest instance
IP Range Any standard host IP x.x.x.255 or 255.255.255.255 224.0.0.0 – 239.255.255.255 (Class D) Same IP on multiple hosts
Crosses Routers? Yes NO Yes (with IGMP) Yes (via BGP)
IPv6 Support? Yes NO — eliminated Yes Yes (native)
Example Web browsing, SSH ARP, DHCP Discover IPTV, OSPF updates DNS root, CDN edge
Efficiency One copy per receiver — scales poorly for groups All devices process — high CPU on large segments One send, network replicates — efficient Nearest server handles load — efficient
Exam Tip
The two "NO" cells are where exam questions hide: broadcast does not cross routers, and IPv6 has no broadcast. Know both cold.
N10-009
Traffic Types

Exam Scenarios

Read each scenario and identify the traffic type before clicking to reveal.

Scenario 1
A switch receives a frame destined for FF:FF:FF:FF:FF:FF. What type of traffic is this?
Broadcast
FF:FF:FF:FF:FF:FF is the broadcast MAC address. The switch floods this frame out every port except the one it arrived on. Common for ARP requests and DHCP Discover.
Scenario 2
A user in Tokyo queries a DNS root server. The same IP address is hosted in Tokyo, London, and New York. Which server responds?
Anycast — nearest instance (Tokyo)
Multiple physical servers share the same IP. BGP routing directs the query to the topologically nearest one. The user in Tokyo hits the Tokyo instance without any application-layer logic.
Scenario 3
OSPF sends routing update packets to address 224.0.0.5. What type of traffic is this?
Multicast
224.0.0.5 is the "All OSPF Routers" multicast group address (Class D). Only routers participating in OSPF join this group and process the updates. Non-OSPF hosts ignore the traffic entirely.
Scenario 4
Your browser connects to 93.184.216.34 to load a webpage. What type of traffic is the HTTP request?
Unicast
93.184.216.34 is the IP for example.com — a single destination host address. Your browser sends TCP packets addressed specifically to that IP. All other hosts on the internet ignore your traffic completely.
N10-009
Traffic Types

Summary

Unicast
One sender
One receiver
Broadcast
One sender
All hosts
Multicast
One sender
Subscribers only
Anycast
One sender
Nearest instance
Remember
Unicast = one, Broadcast = all on segment, Multicast = group of subscribers, Anycast = nearest instance. Each serves a distinct use case — and each appears on the N10-009.
Critical Exam Fact
IPv6 eliminated broadcast entirely. Every function that broadcast handled in IPv4 — neighbor discovery, router solicitation, multicast listener queries — is done with multicast in IPv6. If a question asks about IPv6 and broadcast, the answer is: it does not exist.