Bridged CO In This Chapter This section provides information about Bridged CO model of Triple Play Service Delivery Architecture (TPSDA). Topics in this section include: • Applicability on page 1990 • Summary on page 1991 • Overview on page 1992 • Configuration on page 1998 • Conclusion on page 2029 7750 SR Advanced Configuration Guide Page 1989 Applicability Applicability This section is applicable to the 7750 SR and 7450 ESS series and was tested on SR-OS 7.0 R4. Chassis mode B or higher must be used. The 7750 SR-c4 is supported from 8.0R4 and higher. This note is related only to the use of IPv4 DHCP hosts. Page 1990 7750 SR Advanced Configuration Guide Bridged CO Summary This section provides information about basic technology, network topology and configuration examples which are used in Bridged CO model of Triple Play Service Delivery Architecture (TPSDA). Regardless of aggregation technologies which are used by customers Alcatel-Lucent offers flexible and easy to use methodology to manage DHCP subscribers in Layer 2 domain and distribute subscriber management intelligence across multiple nodes. Knowledge of the Alcatel-Lucent Triple Play Service Delivery Architecture (TPSDA) concepts is assumed throughout this section. 7750 SR Advanced Configuration Guide Page 1991 Overview Overview Bridged CO is a basic TPSDA model and implies that access nodes are united in one Layer 2 aggregation network and VPLS is used as a primary technology for these purposes. This fact allows the use of subscriber management functionality on BSA nodes. Bridged CO network topology is shown in Figure 311. DSL, VoIP Internet GPON IES/ VPLS VPRN BSA BSAN BSR RADIUS Video Server DHCP Aggregation Services Network Network OSSG441 Figure 311: Bridged CO Network Topology Following types of nodes are defined in Bridged CO model: • Broadband Service Access Node (BSAN) — Access node connected to Layer 2 domain to aggregate all traffic from subscribers (IP DSLAM, ethernet switch). • Broadband Services Aggregator (BSA) — Layer 2 node, which is capable for subscriber management in VPLS service (7450 ESS). • Broadband Service Router (BSR) — Layer 3 node, which is capable for routing and service allocation (7750 SR). As any model, Bridged CO introduces several key concepts that must be determined in advance. Major ones are presented in Figure 312 and include: • Subscriber— A set of hosts belonging to a single connection line (switch port, DSL line) • Subscriber host — Unique customer device (could be PC, IP phone, STB, routed CPE). • Subscriber-profile — Configured entity which defines the aggregate QoS for all hosts within a subscriber context. • SLA-profile — Configured entity which defines QoS policies and filters for a subset of hosts within a subscriber context. Page 1992 7750 SR Advanced Configuration Guide Bridged CO • Subscriber identification policy — Configured entity which defines the python script for dynamic subscriber host identification • Authentication policy — Configured entity which defines the RADIUS servers to use for dynamic subscriber host identification • Subscriber identification string — 32 characters identification string which uniquely identifies a subscriber on a node. SAP-1 Sub-1 Scheduler (HSI) Sub-2 SAP-2 Sub-1 Interface (VoIP) Sub-2 SAP-3 Sub-1 Scheduler (Video) Sub-2 Subscriber BSA Subscriber Host Subscriber SAP SLA Profile Subscriber Profile OSSG447 Figure 312: Key Concepts of Bridged CO Model For normal operation each subscriber has to get several parameters / attributes: • Subscriber-ID — Attribute, which uniquely identifies subscriber on the node and used as index key in subscriber database • IP parameters — Attributes, which allows host to get access to services • Subscriber profile and SLA — Profile for subscriber host aa set of filters and QoS policies. • Lease time — Period when subscriber parameters are kept in subscriber database on the node. 7750 SR Advanced Configuration Guide Page 1993 Overview There are several methods how to get each of these parameters: • Static • Python scripts • RADIUS • DHCP Each of the subscriber parameters could be defined in several ways simultaneously. In this case use the following algorithm for selecting: Step 1. For subscriber profile Step 1.1 A lookup in the subscriber-explicit-map is performed with the sub-ident string returned by the Python script, RADIUS or statically configured. If a matching entry is found, the sub-profile-name (if defined) is taken. If no entry was found go to Step 1.2. A:BSA>config>subscr-mgmt# info explicit-subscriber-map entry key "Sub-1" sub-profile "sub-profile-1" sla-profile "sla-profile-1" Step 1.2 If a sub-ident-policy is defined on the SAP, a lookup is done on its sub-profile- map with the sub-profile string from the script. The sub-profile-name is taken from the entry. If no entry was found go to Step 1.3. A:BSA>config>service>vpls>sap# info sub-sla-mgmt sub-ident-policy "sub-ident-policy-1" A:BSA>config>subscr-mgmt# info sub-ident-policy "sub-ident-policy-1" create sub-profile-map entry key "sub-1" sub-profile "sub-profile-1" Step 1.3 If provisioned, the sub-profile-name is taken from the def-sub-profile attribute on the SAP. If no entry was found go to Step 1.4. A:BSA>config>service>vpls>sap# info sub-sla-mgmt def-sub-profile "sub-profile-1" Step 1.4 If a sub-profile with the name default is provisioned. If no entry was found DHCP Ack is dropped. A:BSA>config>subscr-mgmt# info sub-profile "default" create Page 1994 7750 SR Advanced Configuration Guide Bridged CO Sub-ident string is returned by Python script, RADIUS or statically configured Found Found Found Found NO Correspondence in NO Correspondence in NO Sub-profile Correspondence in sub-profile-map def-sub-profile with name subscriber-explicit-map on SAP on SAP “default” YES YES YES YES NO Accept and use Reject DHCP Ack OSSG451 Figure 313: Flow Chart for Subscriber-Profile Identification Algorithm Step 2. For SLA profile Step 2.1 The sla-profile-name is taken from the sub-ident string (returned by the Python script, RADIUS or statically configured) in the subscriber-explicit-map. If no entry was found go to Step 2.2. A:BSA>config>subscr-mgmt# info explicit-subscriber-map entry key "Sub-1" sub-profile "sub-profile-1" sla-profile "sla-profile-1" Step 2.2 A lookup with the sla-profile string from the script is done in the sla-profile-map of the sub-profile found earlier. The corresponding sla-profile-name is used. If no entry was found go to Step 2.3: A:BSA>config>subscr-mgmt# info sub-profile "sub-profile-1" create sla-profile-map entry key "sla-1" sla-profile "sla-profile-1" Step 2.3 The sla-profile-name is taken from sla-profile-map of the sub-ident-policy configured on the SAP. The corresponding sla-profile-name is used. If no entry was found go to Step 2.4. A:BSA>config>service>vpls>sap# info sub-sla-mgmt sub-ident-policy "sub-ident-policy-1" A:BSA>config>subscr-mgmt# info sub-ident-policy "sub-ident-policy-1" create sla-profile-map entry key "sla-1" sla-profile "sla-profile-1" 7750 SR Advanced Configuration Guide Page 1995 Overview Step 2.4 The sla-profile-name is taken from the def-sla-profile attribute on the SAP. If no entry was found DHCP Ack is dropped. A:BSA>config>service>vpls>sap# info sub-sla-mgmt def-sla-profile "sla-profile-1" Sla-profile string is returned by Python script, RADIUS or statically configured Found Found Found Found Correspondence in Correspondence in Correspondence in Correspondence in NO sub-profile-map NO sla-profile-map NO sub-indent string in def-sla-profile of sub-profile of sub-ident-policy subscriber-explicit-map on SAP found earlier on SAP YES YES YES YES NO Accept and use Reject DHCP Ack OSSG452 Figure 314: Flowchart for SLA-Profile Identification Algorithm Note: static configuration has priority over RADIUS configuration and RADIUS has priority over DHCP/Python scripts. Note: each host can have different SLA-profile, while sub-profile applies to whole subscriber. The last definition of sub-profile will force all previously defined hosts to change their sub-profile. Bridged CO supports typical access node connection models, such as: • One VLAN per service (ESM for subscriber differentiation and SAP for service) • One VLAN per subscriber (SAP for subscriber differentiation and QoS flag for service) • One VLAN per access node (ESM for subscriber differentiation and QoS flag for service) Each of these modes has its pros and cons, but this is out of scope of this document. This configuration guide focuses on configuration of one subscriber with three different hosts. VLAN per service is used as mode of subscriber aggregation and mixed RADIUS and DHCP as subscriber identification method. IP termination is done in IES service of BSR. Page 1996 7750 SR Advanced Configuration Guide Bridged CO Correlation of BSA/BSR services and subscriber hosts is presented in Table 20. Table 20: Correlation of Hosts and BSA/BSR Services BSA (Service/Features) BSR (Service/Features) Host-1 VPLS-100 IES-100 ca:00:0c:54:00:08 • DHCP proxy server • SAP/SDP DHCP snoop • Sub-Ident origin via RADIUS • Sla/Sub-profiles via RADIUS • IP options via RADIUS Host-2 VPLS-200 IES-200 ca:01:08:10:00:08 • SAP/SDP DHCP snoop • DHCP relay • Sub-Ident origin through RADIUS • Sla/Sub-profiles through RADIUS • IP options through DHCP Host-3 VPLS-300 IES-300 ca:02:02:d0:00:08 • SAP/SDP DHCP snoop • DHCP relay • Sub-Ident origin through DHCP • Sla/Sub-profiles through DHCP • IP options through DHCP Different methods of authentication and address allocation were chosen for demonstration purposes. The customer is not limited to one method and can use a combination of methods as presented in this guide. The following entities should be configured in advanced. Refer to the appropriate platform user guide for specific information. See Preface on page 37 for a list of documents. • Basic router configuration (interfaces, routing protocols, MPLS) • External RADIUS server • External/Local DHCP server 7750 SR Advanced Configuration Guide Page 1997 Configuration Configuration A sample topology is presented in Figure 315 RADIUS Video Server SAP 1/1/1 IES/ VPLS VPRN BSA VoIP BSR Internet VLAN 100 VPLS- spoke-sdp IES- 100 100 VLAN 200 VPLS- spoke-sdp IES- 200 200 VLAN 300 VPLS- spoke-sdp IES- 300 300 OSSG446 Figure 315: Sample Topology Bridged CO model requires certain techniques and features to be used on different nodes. Major methods are presented in Figure 316. Interface DHCP Loopback SAP SDP Interface DHCP VPLS IES RADIUS Host BSA BSR DHCP Client DHCP Snoop DHCP Snoop DHCP Relay Local DHCP RADIUS DHCP Proxy Server L2 DHCP Relay OSSG442 Figure 316: Functionality of Each Node Page 1998 7750 SR Advanced Configuration Guide