Questions about bridges usually arise when expanding legacy office networks. Should you still consider bridge devices? What exactly do the main options offer? Which works best for your needs? This guide tackles it all – minus the fluff!
I‘ll break down the core capabilities of 3 prevalent bridge types: transparent, source routing, and translational. You‘ll get insider details on the strengths (and weaknesses) of each.
Equipped with this intel, you‘ll make the optimal choice when upgrading your network. Let‘s get bridging!
Bridge Technologies at a Glance
Before analyzing specifics, here is a high-level snapshot of the capabilities:
Transparent bridges – Simple "plug-and-play" tools for quickly interconnecting Ethernet LAN segments. Learn MAC addresses automatically. Limited control.
Source routing bridges – Sophisticated traffic shaping via configurable static/dynamic data routes. Enables secure "micro-segmentation".
Translational bridges – Connect disparate network types by converting protocols and frames "on the fly". Retain existing infrastructure during upgrades.
Now let‘s dive deeper into what sets each technology apart.
Demystifying Transparent Bridging
The simplicity of transparent bridging made this the go-to option historically for wiring offices quickly. They excel at:
Expanding Ethernet segments – Add a bridge to double port capacity versus buying pricier core switches. mitigates congestion as networks grow.
Rapid office wiring – Zero manual configuration means even non-techies can hookup devices to a unified network fast. Get all staff accessing shared printers/servers immediately.
Under the hood, the spanning tree protocol detects cabling issues or equipment failures automatically. It computes backup paths, preventing single points of failure. Convergence times have dropped from minutes in early versions to sub-second.
Fun Fact: Cisco‘s switches evolved from software created for managing transparent bridges!
However, rudimentary MAC address filtering means security and traffic shaping capabilities are weak. Plus throughput maxes out at 100 Mbps per bridge – bottlenecks emerge as networks carry more modern traffic.
Source Routing – Traffic Control and Security
The drive for design flexibility and tighter security spawned source routing bridge architectures. These empower network architects to regulate traffic similar to Layer 3 routers.
Configurable routing tables act like road signs – packets follow prescribed bridge-to-bridge paths based on criteria like:
- Traffic Type (VoIP, internet, etc.)
- Source/Destination MAC addresses
- Time-of-day
Tables populate via static routes defined manually or dynamic routing protocols (RIP, OSPF, etc). SDN controllers even allow centralized programming.
Micro-segmentation helps lock-down bridges between workgroups. Only whitelisted traffic passes while spoofing attempts are discarded immediately. Such integrated security can help compliance.
However, complexity has tradeoffs – more training to configure/maintain. Denial-of-service attacks can still target route tables. And improved routing chips continue narrowing the performance gap versus Layer 3 options.
Translational Bridges – Connecting Disparate Networks
While transparent and source routing bridges link similar LANs, translational varieties take on protocol and hardware bridging between different technologies.
This empowers companies to retain existing analog phone systems or Token Ring networks alongside newer Ethernet infrastructure. Protocol-conversion modules installed in the bridge handle encapsulation, bit-level conversion, and media adaptation automatically.
For example, a translational bridge with:
- FDDI on the backend
- Ethernet to the front-end core
means legacy FDDI devices continue accessing WAN links transparently after an upgrade. No need to discard specialized gear costing hundreds of thousands!
Alas, such versatility comes at a cost – bridging rarely exceeds 50% throughput. And as legacy protocols fade, suitable conversion modules become rare. Evaluating cutover timelines to all-IP infrastructure makes sense.
Do Bridges Still Warrant Consideration?
Given the premiere of wireless mesh and switches with built-in routing, when should bridges still make your shortlist?
Keep bridges in mind if you need:
- Traffic segmentation for security/performance across Ethernet backbones
- Protocol conversion to retain legacy telephony/niche gear during upgrades
- Cascading expansion via cheap ports if switches are already stacking enabled
- Gradual phasing between network architecture generations
For greenfield builds, default to switches with VLAN capabilities instead. Mesh networks similarly relativize the need for bridging wireless traffic over distance.
Focus bridges within specific integration use cases where they alleviate transition pains cost-effectively. Embrace full programmability elsewhere!
I hope demystifying these key bridging protocols helps you make savvy decisions boosting your network capabilities in sync with business needs! Feel free to ping me with any follow-up questions.
To researching optimal technologies together,
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