Provider Ethernet VLAN Cross Connect

1. Provider Ethernet Network Challenges
Business and residential customers require an SLA with guaranteed bandwidth, jitter and
delay
Network resiliency with ~50ms recovery
Huge number of MAC addresses in a single EThernet domain
Scalable VLAN networks to provide dedicated VLAN per customer in wholesale solutions
Networks and services must be secured
Networks should be kept simple to minimize CAPEX
Voice
IP/MPLS
Metro Aggregation
ISPs
ASPs

2. VLAN Cross Connect Taking Ethernet One Step Further
Connection-Oriented technique
Enables traffic engineering and fast recovery
Resolves MAC scalability
Resolves VLAN scalability
Inherent subscriber identification
Voice
Resolves security issues
IP/MPLS
Keep the Network simple
VLAN Cross Connect
Metro Aggregation
ISPs
ASPs

3. Service Model
Destination MAC Source MAC C-tag Ether Type / Len Data FCS
Destination MAC Source MAC S-tag C-tag Ether Type / Len Data FCS
At the boundary of the VLAN-XC domain, the VLAN ID of the outer tag (C-tag or S-Tag)
can be used to associate the frame with a particular VLAN-XC connection.
If required, the outer tag (C-tag or S-tag) is preserved and transparently transported
within the VLAN-XC domain

4. Concept
Standard VLAN Bridging: Switching based on MAC addresses and VLANs
VLAN Cross Connect: Cross Connect according to the ingress port and the VLAN-XC Tag,
regardless of the MAC addresses
Ingress Layer 2 packet
Destination MAC Source MAC VLAN Tag Ether Type / Len Data FCS
Ingress
Port i
Destination MAC Source MAC VLAN Tag Ether Type / Len Data FCS
VLAN Cross Connect coexists with standard VLAN bridging, even on the same port
VLAN Cross Connect eliminates MAC learning per VLAN
VLAN Cross Connect enables up to 16M connections per port

5. Bridging / VLAN Cross Connect Selector
VLAN ID of the frame’s outer VLAN tag acts as method selector
Frame's Outer 802.1Q VLAN Tag
802.1Q/ah Tagged Frame
Destination MAC Source MAC TPID TCI Ether Type / Len Data FCS
C
PCP F VLAN ID
I
Bridging Method VLAN-XC Method
C C
Destination MAC PCP F VLAN ID Ingress Port PCP F VXC ID
I I

6. Frame Semantic
VLAN Cross Connect identifier has local port scope
Frame format as defined in IEEE 802.1Q
VLAN Cross Connect tagged frame allows up to 4K VLANs per port
VXC-TAG
Destination MAC Source MAC TPID TCI Ether Type / Len Data FCS
C
12-bit VLAN Cross Connect ID
PCP F VXC ID
up to 4K VLANs per port
I

7. Frame Semantic
Extended VLAN Cross Connect
Frame Format as defined in IEEE 802.1ad
VLAN Cross Connect tagged frame allows up to 16M VLANs per port
EVXC-TAG
Destination MAC Source MAC TPID TCI TPID TCI Ether Type / Len Data FCS
C C
PCP F VLAN ID PCP F VLAN ID
I I
24-bit VLAN Cross Connect ID
EVXC ID
up to 16M VLANs per Port

8. Process Example
In Port Ingress VLAN OUt Port Egress VLAN
1 10 7 110
2 10 5 120
3 30 5 130
3 40 6 130
4 40 7 140
4 50 Bridging according to MAC Destination and VLAN ID 50
Cross Connect VID=120
VID=10 Port 1 Port 5
VID=130
VID=130
VID=10 Port 2 Port 6
VID=50
VID=30 VID=110
Port 3 Port 7
VID=40
VID=140
VID=40
Port 4 Bridge Port 8 VID=50
VID=50

9. Network Reference Model
PE-Node P-Node P-Node PE-Node
P-Node
PE-Node P-Node P-Node PE-Node
Provider Edge Nodes (PE-Nodes) reside at the boundary of the provider network and
create / terminate VLAN-XC connections
Provider Internal Nodes (P-Nodes) perform VLAN Cross Connect switching

10. VLAN Cross Connect with CE-VLAN Preservation Example
VLAN Cross Connect Connection
PE-Node P-Node P-Node PE-Node
L2 L2 L2 L2 L2
Frame Frame Frame Frame Frame
Port 3 Port 6 Port 2 Port 8 Port 4 Port 12 Port 6 Port 9
Destination MAC Destination MAC Destination MAC Destination MAC Destination MAC
Source MAC Source MAC Source MAC Source MAC Source MAC
CE-VLAN VXC=1024 VXC=236 VXC=2636 CE-VLAN
CE-VLAN CE-VLAN CE-VLAN

11. Extended VLAN Cross Connect Example
VLAN Cross Connect Connection
PE-Node P-Node P-Node PE-Node
L2 L2 L2 L2 L2
Frame Frame Frame Frame Frame
Port 3 Port 6 Port 2 Port 8 Port 4 Port 12 Port 6 Port 9
Destination MAC Destination MAC Destination MAC Destination MAC Destination MAC
Source MAC Source MAC Source MAC Source MAC Source MAC
CE-VLAN CE-VLAN
EVXC=12045 EVXC=645 VXC=15320
CE-VLAN CE-VLAN CE-VLAN

12. Traffic Engineering
E-line between two business customer sites
Site A Site B
Selected bridged path for traffic between Site A and Site B
Traffic-engineerred path with guaranteed QoS
VLAN Cross Connect enables traffic engineering
Can be implemented using a domain-wide provisioning tool
GMPLS control plane once standardized

13. VLAN Cross Connect Network Resiliency
Protected XC
1:1
Backup XC
1:1 Global Protection with extra traffic
Pre-provisioned backup paths using network-wide provisioning tools
Sub-50ms recovery
Revertive or non-revertive mode
GMPLS resiliency mechanisms could be applied once GMPLS for Ethernet is standardized
( include Fast Reroute)

14. Scalability
EVXC EVXC
MAC
Tag Tag
EVXC EVXC
MAC
Tag Tag
Level n+1
EVXC
EVXC MAC
MAC Tag
Tag
EVXC
EVXC MAC
MAC Tag
Tag
Level n Level n
VLAN Cross Connect can be naturally extended to work with hierarchical domains using
tunneling
Uses standard VLAN stacking

15. Reference Documents
Provider Ethernet VLAN Cross Connect by Philippe Klein, Nurit Sprecher - Siemens
Surpass Carrier Ethernet Jan 2006
IEEE Standard 802.3 ,CSMA/CD Ethernet
IEEE Standard 802.1Q ,Virtual LAN
IEEE Standard 802.1ad ,Q-in-Q
IEEE Standard 802.1ah draft ,MAC-in-MAC