Specifications

CHAPTER 1
Campus Network Design
Network Traffic Flow
The need for a core layer and the devices chosen for the core also depend on the type of network traffic and traffic flow
patterns. Modern converged networks include different traffic types, each with unique requirements for security, QoS,
transmission capacity, and delay. These include:
n IP telephony signaling and media
n Core Application traffic, such as Enterprise Resource Programming (ERP), Customer Relationship Management
(CRM)
n Multicast multimedia
n Network management
n Application data traffic, such as web pages, email, file transfer, and database transactions
n Scavenger class traffic that requires less-than-best-effort treatment
The different types of applications also have different traffic flow patterns. These might include:
n Peer-to-Peer applications such as IP phone calls, video conferencing, file sharing, and instant messaging provides
real-time interaction. It might not traverse the core at all, if the users are local to each other. Their network require-
ments vary, with voice having strict jitter needs and video conferencing using high bandwidth.
n Client-Server applications require access to servers such as email, file storage, and database servers. These servers
are typically centralized in a data center, and users require fast, reliable access to them. Server farm access must also
be securely controlled to deny unauthorized users.
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CCNP SWITCH 642-813 Quick Reference by Denise Donohue