Access Networks practice Moldovn Istvn Dimensioning IPTV - - PowerPoint PPT Presentation

Access Networks – practice Moldován István

Tutorial Access Architecture — 2

Dimensioning

 IPTV

• Streaming: multicast

– Bandwidth demand = channel * video rate

• VoD: unicast

– Bandwidth demand = estimated # of users watching* video rate

 VoIP

• Call bandwidth demand : codec dependent data + header overhead
• Bandwidth demand = estimated # of simultaneous calls (Erlang) * call

bandwidth demand

 HSI

• Premium service: the sum of reserved bandwidth
• Best Effort Internet: different methods to estimate
• Strategy: 50% on links should be reserved for Best Effort

– Drop in case of congestion

Tutorial Access Architecture — 3

Mac Forced Forwarding

 DSLAM only sends to BNG

• All other dropped

 Operation:

• PPP: sends to BRAS only
• IPoE:

– ARP request results in BNG address always – Packets sent to other destinations dropped

• Can also be done with VLANs

Tutorial Access Architecture — 4

QoS support

Priority based on 802.1Q VLAN tag

• 3 bit = 8 classes

The priority bits described in 802.1p

• VLAN priority and IP TOS are similar
• Not all switches support 8 classes
• P-bits are in VLAN header, but not associated to the ID

VLAN ID (12 bit) 802.1p (3 bit) CFI (1 bit) 802.1Q VLAN TAG

P-bits

Tutorial Access Architecture — 5

Technology and planning

 Spanning Tree restrictions  Traffic management

• Traffic identification
• Addressing
• mapping

 QoS  Protection

5

Tutorial Access Architecture — 6

Spanning Tree

6 HSI Voice Video

Internet

STB RGW DSLAM Video Server Forrás SoftSwitch PBX STB RGW Coax DSL BRAS BNG

Where is the root? Traffic engineering?

Tutorial Access Architecture — 7

 Thank you for your attention!

• Questions?