Glossary

Definitions of technical and product terms used across this documentation. Most terms link to the pages where they appear in context.

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Definitions of technical and product terms used across this documentation. Most terms link to the pages where they appear in context.

A

Active-Active - A redundancy pattern where two connections carry production traffic simultaneously, with path preference controlled by BGP attributes such as local preference and AS-PATH.

Active-Passive - A redundancy pattern where one connection carries production traffic while a second standby connection takes over on failure. Switchover is usually triggered by BGP session loss or BFD.

ASN (Autonomous System Number) - A globally unique number assigned to a network for use with BGP. Each side of a BGP session declares its ASN. Tata Communications uses ASN 4755 on the GVPN side of IZO™+ Multi Cloud Connect connections.

AWS Direct Connect - Amazon’s service for establishing a dedicated network connection between an on-premises network and AWS. IZO™+ Multi Cloud Connect delivers Direct Connect as a managed service via Hosted Connections.

Azure ExpressRoute - Microsoft’s service for extending on-premises networks into Azure over a private connection. IZO™+ Multi Cloud Connect delivers ExpressRoute as a managed service.

Bandwidth slab - A specific bandwidth tier offered for an IZO™+ Multi Cloud Connect connection. Slabs are cloud-provider-specific; for example, AWS supports 50 Mbps to 25 Gbps and Azure supports 50 Mbps to 10 Gbps.

BFD (Bidirectional Forwarding Detection) - A protocol for sub-second detection of link failures, paired with BGP to accelerate failover between redundant connections.

BGP (Border Gateway Protocol) - The dynamic routing protocol used between a customer network and a cloud provider over IZO™+ Multi Cloud Connect. BGP advertises prefixes, controls path selection, and enables fast failover.

Class of Service (COS) - A QoS marking used to prioritise traffic on the Tata Communications MPLS backbone. IZO™+ Multi Cloud Connect connections are typically configured with a single COS class to provide consistent quality of service.

Cloud-to-Cloud Connectivity - A deployment pattern where two or more public clouds are interconnected privately through IZO™+ Multi Cloud Connect, eliminating the public-internet path between them.

CPE (Customer Premise Equipment) - The customer-side network device (typically a router) that terminates the IZO™+ Multi Cloud Connect connection at the enterprise site. CPE can be managed by Tata Communications or by the customer.

Cloud VC (Cloud Virtual Circuit) - The logical connection between IZO™+ Multi Cloud Connect and a cloud provider’s on-ramp that carries a customer’s traffic to that cloud.

C-tag (Customer tag) - The inner VLAN tag (Q-in-Q). On Azure the C-tag is fixed by peering type: 113 for Private Peering and 115 for Microsoft Peering.

Deployment scenario - The topology in which IZO™+ Multi Cloud Connect is deployed at the customer side. The four supported scenarios are Full Mesh, Hub-and-Spoke, Cloud-to-Cloud, and Selected Site.

DRG (Dynamic Routing Gateway) - Oracle Cloud Infrastructure’s edge routing component, attached to FastConnect connections to exchange routes with the customer network.

DMVPN (Dynamic Multipoint VPN) - The multi-site internet-underlay model for IZO™+ Multi Cloud Connect Flex, in which the nearest Service Gateway acts as the hub for the customer’s sites.

ExpressRoute Direct - A high-capacity variant of Azure ExpressRoute offering port pairs at 10 or 100 Gbps. Customers requiring sustained multi-gigabit throughput choose ExpressRoute Direct over standard ExpressRoute.

EoMPLS (Ethernet over MPLS) - The Layer 2 point-to-point transport used to deliver L2VPN connections across the Tata Communications MPLS backbone.

Extended Access Services (EAS) - The internet-underlay access method that underpins IZO™+ Multi Cloud Connect Flex: route-based IPsec to a Service Gateway for a single site, or DMVPN to the nearest Service Gateway for multiple sites.

FastConnect - Oracle Cloud Infrastructure’s private connectivity service. IZO™+ Multi Cloud Connect delivers FastConnect as a managed service.

Full Mesh Topology - A deployment where every customer site can reach every other site directly through the GVPN backbone, with no central hub.

Fabric Port - The customer’s logical entry point into IZO™+ Multi Cloud Connect, delivered over a shared cloud-facing port. Each connection is carried as a logical circuit on a Fabric Port.

GSTIN (Goods and Services Tax Identification Number) - The Indian tax registration identifier collected during TC^x Portal sign-up for customers in India. Required for billing and invoicing.

GVPN (Global Virtual Private Network) - Tata Communications’ MPLS backbone. IZO™+ Multi Cloud Connect services are delivered over GVPN.

High Availability (HA) - A design pattern in which redundant components ensure service continuity in the event of a failure. For IZO™+ Multi Cloud Connect, HA typically means two physical connections to a cloud provider, with BGP managing failover.

Hosted Connection - A logically partitioned AWS Direct Connect connection delivered over a Tata Communications-managed or Equinix-routed interconnect. Supports a single VLAN per connection and bandwidths from 50 Mbps to 25 Gbps.

Hub-and-Spoke Topology - A deployment where a central hub site brokers connectivity for a set of remote spoke sites. All spoke-to-cloud and spoke-to-spoke traffic transits the hub.

Hosted Virtual Connection (HVC) - In IZO™+ Multi Cloud Connect Flex, the connection between the Fabric Port and the virtual network function (VNF) that sits in the traffic path ahead of the cloud virtual circuit.

IPsec (Internet Protocol Security) - A protocol suite for encrypting and authenticating IP packets. Used in IZO™+ Multi Cloud Connect when an enterprise site connects over the public internet rather than MPLS, encrypting the underlay link.

IZO™ - Tata Communications’ family of cloud-connectivity products. IZO™+ Multi Cloud Connect (MCC) is one member of the family.

IZO™+ MCC - Tata Communications’ private cloud connectivity service that links enterprise networks to AWS, Azure, GCP, Oracle, and IBM Cloud through dedicated interconnects.

IZO™+ MCC Flex - The NFV-based variant of IZO™+ Multi Cloud Connect that delivers connectivity through virtualised network functions (router, firewall, SD-WAN) rather than physical interconnects.

IZO™+ MCC Secure - The variant of IZO™+ Multi Cloud Connect that integrates Firewall-as-a-Service for end-to-end inspection of cloud-bound traffic.

KYC (Know Your Customer) - The identity-verification step in the TC^x Portal sign-up flow, where the customer’s legal entity, GSTIN, and address are validated before billing can begin.

Legal Entity - The registered business name under which the customer subscribes to IZO™+ Multi Cloud Connect. Collected during sign-up and used on all contracts and invoices.

Looped Interface - The architectural pattern in the IZO™+ Multi Cloud Connect modular design where a single GVPN /MPLS PE router has an internal loopback connection: one end terminates the GVPN / MPLS service VPN, the other end terminates the cloud Virtual Circuit. This allows the two layers to be provisioned independently.

MACsec - IEEE 802.1AE Layer-2 encryption protocol, available on supported AWS Direct Connect configurations for line-rate encryption between the customer port and AWS.

MPLS (Multiprotocol Label Switching) - The packet-forwarding technology that underpins Tata Communications’ GVPN backbone. Provides traffic engineering, QoS, and VPN isolation.

MRC / NRC (Monthly Recurring Charge / Non-Recurring Charge) - The two pricing components for IZO™+ Multi Cloud Connect. MRC is the ongoing monthly fee for bandwidth; NRC is the one-time setup charge.

MSEE (Microsoft Enterprise Edge) - Microsoft’s edge routers used to terminate Azure ExpressRoute circuits. IZO™+ Multi Cloud Connect peers with two MSEE routers per ExpressRoute circuit for redundancy.

MTU (Maximum Transmission Unit) - The largest packet size supported on a network link. Standard MTU is 1500 bytes; jumbo MTU (typically 9000 bytes) is supported on some IZO™+ Multi Cloud Connect interconnects to improve throughput.

Microsoft Peering - The Azure ExpressRoute peering type used to reach Microsoft public services (for example Microsoft 365), distinct from Private Peering.

NFV (Network Function Virtualization) - The practice of running network functions (routing, firewalling, SD-WAN) as virtual machines on commodity hardware rather than dedicated appliances. IZO™+ Multi Cloud Connect Flex is built on NFV principles.

NGE (Next Generation Encryption) - A modern suite of cryptographic algorithms supported on IZO™+ Multi Cloud Connect Service Gateway routers for customers using IPsec underlays.

NNI (Network-to-Network Interface) - The interconnect between the Tata Communications network and another network - a cloud provider on-ramp or a partner network - over which connections are delivered.

OTP (One-Time Password) - A short, time-limited code sent to the customer during TC^x Portal sign-up to verify their email address and mobile number.

PE Router (Provider Edge Router) - A router on the edge of the Tata Communications MPLS backbone that terminates customer connections. IZO™+ Multi Cloud Connect services are provisioned on GVPN PE routers.

PoP (Point of Presence) - A physical location where Tata Communications operates network infrastructure. Each PoP is a potential entry point to the MPLS backbone.

Private Peering - The Azure ExpressRoute peering type used to reach private Azure resources in customer VNets. Distinct from Microsoft Peering, which reaches public Azure services.

Public Peering - The AWS Direct Connect peering type used to reach public AWS services (EC2, S3, DynamoDB, etc.) over the dedicated connection rather than the public internet.

Pairing key - The identifier generated in a Google Cloud project that the customer supplies to attach a Partner Interconnect.

QinQ (802.1ad) - A VLAN-stacking technique where one VLAN tag is encapsulated inside another. Used between Tata Communications MPLS PE routers and AWS Direct Connect interconnects to manage customer VLANs at scale.

Resiliency model - The redundancy tier chosen for a connection: Standard (in-metro dual path), High, or Maximum (cross-region or multi-metro).

Route Filter - A policy that controls which route prefixes are advertised or accepted on a peering. On Azure Microsoft Peering, a route filter selects the Microsoft service communities the customer receives.

Selected Site - A deployment scenario where only specific enterprise sites are connected to a given cloud, useful for staged migrations and limited-scope production cutovers.

Service Gateway - A Tata Communications router that provides Extended Access Services, allowing internet-connected customer sites to reach IZO™+ Multi Cloud Connect services over IPsec.

Service Type - The product category selected in the TC^x Portal when raising a service request or browsing inventory. Examples: GVPN, MPLS, IAS, IZO SDWAN, IZO™+ Multi Cloud Connect Direct.

SLA (Service Level Agreement) - The contractual guarantees Tata Communications provides on availability, latency, packet loss, and jitter for IZO™+ Multi Cloud Connect services.

S-tag (Service tag) - The outer VLAN tag (Q-in-Q) that identifies a customer’s circuit on a shared port. For partner-routed connections it is allocated from the 1300-1399 range, unique per circuit.

Service key - The identifier Microsoft generates for an Azure ExpressRoute circuit, supplied by the customer so the circuit can be linked on the Tata Communications side.

TC^x Portal - Tata Communications’ self-serve customer portal. Used for placing orders, viewing inventory, raising service requests, and monitoring connections.

Transit VIF (Transit Virtual Interface) - An AWS Direct Connect virtual interface attached to a Transit Gateway, providing access to multiple VPCs across multiple AWS regions over a single connection.

Tata Cloud Router (TCR) - A Tata Communications-hosted virtual router that joins two or more cloud virtual circuits so clouds can exchange traffic privately, without hair-pinning through a customer site.

VIF (Virtual Interface) - The BGP peering session over an AWS Direct Connect connection. Three types: Private VIF (VPC access), Public VIF (AWS public services), and Transit VIF (multi-region via Transit Gateway).

VLAN (Virtual LAN) - An 802.1Q tag used to logically separate traffic over a shared physical link. Each IZO™+ Multi Cloud Connect Hosted Connection uses one VLAN.

VNF (Virtualized Network Function) - A network function (router, firewall, SD-WAN) implemented in software and deployed within IZO™+ Multi Cloud Connect Flex.

VPC (Virtual Private Cloud) - An isolated virtual network in a cloud provider’s infrastructure. Customers configure their on-premises network to reach one or more VPCs over IZO™+ Multi Cloud Connect.

VRF (Virtual Routing and Forwarding) - A routing-table partition on a single router that isolates one customer’s traffic from another’s. Used throughout the Tata Communications GVPN backbone.

VC OCID (Virtual Circuit OCID) - The Oracle Cloud Identifier for a FastConnect virtual circuit, supplied by the customer to establish the connection.