Medianet Reference Guide - Cisco

Solution
Chapter 1
Medianet Architecture Overview
latency; however, this value would be greater for intercontinental distances), low jitter (such as less than
5 ms peak-to-peak jitter within the SP network), and lowest practical packet loss (approaching 0-0.05%).
SP burst allowances and capabilities are also factors to consider.
When selecting SPs, the ability to map the company’s QoS classes to those offered by the SP is also
essential. The SP service should be able to preserve Layer 3 DSCP markings and map as many classes
as practical across the SP network. An example enterprise edge medianet mapping to a 6-class MPLS
VPN SP is illustrated in Figure 1-14.
Figure 1-14
Enterprise to 6-Class MPLS VPN Service Provider Mapping Model Example
Application
DSCP
6-Class SP Model
VoIP Telephony
Broadcast Video
EF
CS5
EF
CS5
SP-Real-Time
30%
Realtime Interactive
Multimedia Conferencing
Multimedia Streaming
Network Control
Call Signaling
CS4 CS5
AF4
AF3
CS6
CS3
AF4
CS4
AF3
CS6
CS3
SP-Critical 1
10%
SP-Critical 2
15%
Network Management
Transactional Data
CS2
AF2
CS2
AF2
SP-Critical 3
15%
Bulk Data
Best Effort
Scavenger
AF1
DF
CS1
DF
AF1
CS1
SP-Best Effort
25%
SP-Scavenger
5%
224553
Broadcast Optimization for Branch Offices
IP multicast is supported by the Cisco ISR and ASR product families. Certain SP WAN services may or
may not support the capability to use IPmc over the WAN. For example, if using an MPLS service,
typically the provider must be able to offer a multicast VPN service to allow IPmc to continue to operate
over the MPLS WAN topology.
Similarly, certain WAN topologies and integrated security designs also may preclude the use of IPmc.
For example, IPSec VPNs cannot transport multicast packets natively. Cisco IPSec VPN WANs
combined with Cisco GRE, Cisco Virtual Tunnel Interface (VTI), and Cisco Dynamic Multipoint VPN
(DMVPN) do support multicast traffic.
Scalability of WANs with encryption-enabled can suffer from multicast traffic due to the requirements
to encrypt the same packet numerous times, once for each branch office connection. The Cisco Group
Encrypted Transport VPN (GETVPN) offers a solution, allowing many branch office connections to
share the same encryption key. This is an ideal solution for maintaining the secure connectivity that
VPNs offer, while not compromising scalability when IP multicast is required to be broadcast over the
WAN.
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Medianet Reference Guide
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