Basic Call Flow Using ERE

In this section:

This section provides the basic steps to establish a simple call flow between two end points.

Prerequisites

To establish a SIP call through the SBC Core, an IP Plan (Creating an IP Plan, Creating an IP Plan for SBC SWe on VMware or KVM Hypervisor) must be developed and the following network elements must be installed and interconnected:

SBC server(s)
Far End A (must know the IP address of SBC's SIP port)
Far End B (must know the IP address of SBC's SIP port)
Associated routers

For basic configuration details, refer to:

The EMA figures are for representational purpose only. Please use the values provided in the CLI.

Configure SIP Trunking

In this scenario, trunk group routing is used to send all traffic arriving on "Outside" trunk to "Inside" trunk, and vice versa. This allows for no additional configuration changes on the SBC as the operator adds more numbers to be routed.

This configuration supports G.729A on the "Outside" with G.711 on the "Inside" thus transcoding will occur.
Because a single Address Context is configured in this scenario, no IP address overlapping is allowed.

Both "Outside" and "Inside" specific configuration data must be made. Below is a summary of the key configuration items.

Table 1: Configuring SIP Trunking

Configuration Item	PEER (Outside)	CORE (Inside)
Zone	SIP Port and Trunk Group reside in Zone	SIP Port and Trunk Group reside in Zone
IP InterfaceGroup and IP Interface	Specifies the Interface and Interface Group which resides in the zone	Specifies the Interface and Interface Group which resides in the zone
SIP Signaling Port	public IP address that far end sends messages to	private IP address the feature server sends messages to
Packet Service Profile (PSP)	Specify G.729A	Specify G.711
Codec Entry	Far end codec definitions	Feature server codec definitions
IP Signaling Profile	SIP Parameter settings	SIP Parameter settings
Trunk Group	IP address of where signaling messages arrive from. If the far end is not a dedicated feature server (i.e. phone), set field to 0.0.0.0.	IP address of where signaling messages arrive from – usually set to the feature server's signaling port IP address.
IP Peer	IP address of far end	IP address of feature server
Routing Label	One per trunk group	One per trunk group
Route	One per trunk group	One per trunk group

Zone

Create two new zones for Trunking, each one representing an external customer or operator equipment.

Table 2: Zone

Zone	Purpose
peer	Traffic to/from far end carrier
core	Traffic to/from operator trunking equipment

CLI

From CLI command line, enter following commands to establish two zones (peer, core) using default addressContext:

Create two zones; for peer and for core. For example:

% set addressContext default zone ZONE_IAD id 2
% set addressContext default zone ZONE_AS id 3
% commit

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > Zone

Figure 1: Zone

ipInterfaceGroup and ipInterface

An IP Interface Group is a named object containing one or more IP interfaces (IP addresses). The IP Interface Group is Address Context specific (e.g. permanently bound to a particular Address Context), and is the primary tool to manage disjoint networks (administrative network separation). An IP Interface Group is the local manifestation of a segregated network domain. The service section of an IP trunk group and a Signaling Port typically reference an IP Interface Group in order to restrict signaling and/or media activity to that IP Interface Group

CLI

set addressContext default ipInterfaceGroup LIF1 ipInterface pkt0_v4 ceName CHIVAS portName pkt0 ipAddress 10.54.12.111. prefix 24  
commit
set addressContext default ipInterfaceGroup LIF1 ipInterface pkt0_v4 altIpAddress fd00:10:6b50:4c70::8b altPrefix 60
commit

SIP Signaling Port

SIP Signaling Ports reside on the SBC (e.g. IP addresses are owned by SBC), and are the IP addresses that external devices (non-SBC) send SIP traffic to and receive SIP traffic from. For this example, two new Trunking SIP Ports are created. The term "operator" represents the Carrier, Service Provider, or Enterprise that owns the SBC.

SIP Port #	Zone	Purpose
1	peer	Traffic to/from far end carrier
2	core	Traffic to/from operator trunking equipment

Each SIP Signaling port is in a unique Zone. The non-SBC equipment (phones, operator feature server, other Carriers, operator trunking server) sends/receives SIP messages to/from the IP addresses and port configured. The default protocol is UDP and default port is 5060.

When a SIP Port is created (IP address is assigned), the system also creates an ACL allowing traffic from all source IP addresses to that destination. In other words, an unauthorized entity could attempt to send traffic to the IP address of the SIP Port. To prevent unwanted registration or call attempts at the earliest opportunity within the SBC, manually create ACLs to specify what source IP addresses are allowed toward that SIP Port. Refer to the topic Managing SBC Core System Security for details.

CLI

% set addressContext default zone ZONE_IAD id 2 sipSigPort 1 ipInterfaceGroupName IPIG1 ipAddressV4 <external IP address> state enabled
% set addressContext default zone ZONE_AS id 3 sipSigPort 2 ipInterfaceGroupName IPIG1 ipAddressV4 <internal IP address> state enabled
% commit

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > Signaling Ports > Sip Sig Port

Figure 2: Sip Sig Port

Packet Service Profile (PSP)

Packet Service Profiles control the media settings such as Codec, Packet Size, Transcoding options, and fax support on a trunk group. Each PSP can contain up to four Codec entries using ERE. These Codec entries describe a codec, its packet size and other codec-specific parameters, such as "law" (A or U) for G.711. Several default Codec entries are pre-configured on the system as examples to create your own.

Note

The PSX supports configuring up to 12 codecs in the Packet Service Profile and Preferred Packet Service Profile. The SBC supports receiving all 12 codecs from the PSX in the PSP and Preferred PSP. This applies to interworking with an external PSX (Advanced ERE deployment scenario). See Routing and Policy Management for deployment scenario details.

Additionally, the SBC supports up to 12 codecs over Gateway links to SBCs and/or GSXs.

Note

An SBC-POL-RTU license is needed to enable more than four codecs.

If you do not wish to use the default Codec Entries you will need to create custom Codec Entries before creating Packet Service Profiles since the PSP reference the Codec Entries. For example, you may want to have a PSP that specifies 20ms packet size, RFC2833 transport, allows for G.729A codec, and allows transcoding of G.711 to G.729A.

In our example, two Packet Service Profiles are created.

Create new PSPs based on the default PSP (avoid modifying default PSP), and use a naming convention to identify the function of each PSP.

CLI

% set profiles media packetServiceProfile DEFAULT codec codecEntry1 G711-DEFAULT
% set profiles media packetServiceProfile PSP_1 codec codecEntry1 G729A-DEFAULT
% commit

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > Packet Service P

Codec Entry

The Codec Entry describes one specific codec that can be offered as part of the Packet Service Profile. Several default Codec Entries are included with the SBC. It is recommended to name the Codec Entry in a descriptive manner, so it is easy to select during the Packet Service Profile creation or modification.

In this example, the following default codecs are used:

G711-DEFAULT
G729-DEFAULT

IP Signaling Profile

IP Signaling Profiles control how various SIP egress and ingress parameters are set and processed. Use a unique profile for each type of destination. Each trunk group has an assigned IP Signaling Profile.

A trunk group has both an IP Signaling Profile and an Egress IP Signaling profile. The Egress IP Signaling profile is used for the outgoing signaling (sent from the trunk group).

The IP Signaling profile configured on the IP Peer overwrites the IP Signaling profile configured on the trunk group.

In this example, the IP Signaling Profile "DEFAULT_SIP" is used.

Trunk Group

An important concept on the SBC is that all signaling and routing is based upon Trunk Groups. Even in Access configurations, a set of endpoints is represented by a trunk group.

The standard trunk group naming convention is to always CAPITALIZE trunk group names.

In this example configuration, two SIP trunk groups are created.

Trunk Group Name	Purpose
CORE	Trunk to operator network equipment (carrier that owns the SBC)
PEER	Trunk to far end (another carrier or PBX for example)

CLI

% set addressContext default zone ZONE_IAD sipTrunkGroup TG1 ingressIpPrefix <ingress IP and prefix>
% set addressContext default zone ZONE_IAD sipTrunkGroup TG1 media mediaIpInterfaceGroupName IPIG1
% set addressContext default zone ZONE_IAD sipTrunkGroup TG1 policy media packetServiceProfile DEFAULT
% commit
% set addressContext default zone ZONE_AS sipTrunkGroup TG2 ingressIpPrefix <ingress IP and prefix>
% set addressContext default zone ZONE_AS sipTrunkGroup TG2 media mediaIpInterfaceGroupName IPIG2
% set addressContext default zone ZONE_AS sipTrunkGroup TG2 policy media packetServiceProfile DEFAULT

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > SIP Trunk Group.

Figure 3: SIP Trunk Group

IP Peer

The IP Peer is the IP address of the far end device. The IP Peer is referenced in the Routing Label, and is used for outgoing calls for a particular Trunk Group.

If you define an IP Signaling Profile in the IP Peer, the profile defined the in trunk group is overwritten.

For Access configurations, it is not necessary to have a IP Signaling Peer to the individual phones. You do need one to the feature server.

CLI

% set addressContext default zone ZONE_IAD IpPeer Peer_1 ipAddress <IP address> ipPort 5060
% set addressContext default zone ZONE_AS IpPeer Peer_2 ipAddress <IP address> ipPort 5060
% commit

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > IP Peer

Figure 4: IP Peer

Routing Label

The Routing Label is used by (referenced in) the Route to send traffic from one trunk group to the other, and vice versa. Trunk Group routing is used for this purpose.

One Routing Label is created for each Trunk Group, and is used to send calls to that Trunk group. In the below example, the Routing Label "TO_CORE" sends calls to "CORE" trunk group. There is also a Routing Label "TO_PEER" that sends calls to "PEER" trunk group.

CLI

% set global callRouting routingLabel TO_PEER routingLabelRoute 1 trunkGroup TG1 ipPeer Peer_1 inService inService
% set global callRouting routingLabel TO_CORE routingLabelRoute 2 trunkGroup TG2 ipPeer Peer_2 inService inService
% commit

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > Category: Call Routing > Routing

Figure 5: Routing Label Route

For more information on Routing Label Route, refer to Call Routing: System Provisioning - Routing.

Route

The Route determines how call routing is accomplished. Several methods are available to implement routing (dialed number, carrier, calling number, trunk group, etc.) Trunk Group routing is used for this example configuration, and is the simplest and most straight forward means to implement a "pure" SBC function. It allows the operator to add users (routable numbers) without having to configure those numbers into the SBC.

For Trunk Group routing, calls that arrive on trunk group "CORE" are sent to Routing Label "TO_PEER", which routes the call to trunk group "PEER". In the other direction, calls that arrive on trunk group "PEER" are sent to Routing Label "TO_CORE", which routes the call to the "CORE" trunk group.

In the examples below "DALSBC01" is the name of the SBC.

CLI

% set global callRouting route trunkGroup TG1 DALSBC01 standard Sonus_NULL 1 nationalType nationalType ALL none Sonus_NULL routingLabel TO_CORE
% set global callRouting route trunkGroup TG2 DALSBC01 standard Sonus_NULL 1 nationalType nationalType ALL none Sonus_NULL routingLabel TO_PEER

EMA GUI

On the SBC main screen, navigate to Configuration > System Provisioning > Category: Call Routing > Routing

For more information on Routing Label Route, refer to Call Routing: System Provisioning - Routing.

****YOU ARE NOW READY TO PLACE A TEST CALL****

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Prerequisites

Configure SIP Trunking

Zone

CLI

EMA GUI

ipInterfaceGroup and ipInterface

CLI

SIP Signaling Port

CLI

EMA GUI

Packet Service Profile (PSP)

CLI

EMA GUI

Codec Entry

IP Signaling Profile

Trunk Group

CLI

EMA GUI

IP Peer

CLI

EMA GUI

Routing Label

CLI

EMA GUI

Route

CLI

EMA GUI