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MAC-in-MAC and Transport Scenarios. Paul Buttorf, Michael Chen, Dirceu Cavendish, Marcus Holness, Pankaj Jha, Kshitij Kumar, Dinesh Mohan, Himanshu Shah, Arnold Sodder, Joris Wils . Agenda. Service Provider Transport Scenarios Flat network architecture Q-in-Q network architecture
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MAC-in-MACand Transport Scenarios Paul Buttorf, Michael Chen, Dirceu Cavendish, Marcus Holness, Pankaj Jha, Kshitij Kumar, Dinesh Mohan, Himanshu Shah, Arnold Sodder, Joris Wils
Agenda • Service Provider Transport Scenarios • Flat network architecture • Q-in-Q network architecture • MAC-in-MAC network architecture • Service Provider Hierarchical Architecture
Reference Provider Transport Architecture PE PE Provider Network RB CE CE CE CE Customer Network Customer Network RB Regular bridges
Transport on Flat Network • The example shows four scenarios. The first two are of a provider interconnecting the LANs of 5 customer sites per vlan. The last two are of a provider interconnecting customer routers. • The number of MAC addresses can easily climb into the 100,000’s. • Large FWD tables • Management Issues • MAC address space (customer) • VLAN tag space (customer, provider)
With Q-in-Q • The number of MAC addresses can easily climb into the 100,000’s. • Large FWD tables • Protocol issues • E.g. BPDU encapsulation • Management issues • E.g. unreliable customer links. • Limit on number of service instances (4094)
Number of MAC Addresseswith MAC-in-MAC * * Worst case scenario
Hierarchical Transport Architectures Core (10G links) MAC-in-MAC Aggregation (1G uplinks, 10/100M access links) Q-in-Q Q-in-Q CE CE CE CE Core (10G links) Q-in-Q MAC-in-MAC MAC-in-MAC Aggregation (1G uplinks, 10/100M access links) CE CE CE CE
Number of MAC Addresses with MAC-in-MAC • Equals the number of PEs regardless of the number of vlans and customer MAC addresses, because: • MAC-in-MAC bridges only need to learn the MAC addresses of PE Bridges. • Number of MAC addresses to be managed by providers unlikely to go above 1,000s.
Provider Transport Technologies MAC-in-MAC Q-in-Q CE CE CE CE CE CE CE CE Q-in-Q MAC-in-MAC CE CE CE CE
Additional MAC-in-MAC Features • Trouble free provider protocols • Special MAC addresses mean the same for customer and provider domains. • Transparent transport of control traffic • Customer topology changes do not affect provider MAC learning - No need for MAC unlearn messages • Full isolation from customer’s (R)STP (single homed). • Provider Bridges’ addresses can be configured local MAC addresses.
Final remarks • Message • MAC-in-MAC is an attractive technology with unique characteristics, besides Q-in-Q for Ethernet Service Providers. • Open Issue • Where is it most appropriate to use Q-in-Q and MAC-in-MAC in a Hierarchical L2 Network.