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2.5 Transport Design

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Field Value
Document Title Transport Design
Section Number 2.5
Version 1.0
Last Updated December 30, 2025
Author Network Architecture Team
Classification Internal Use

2.5.1 Transport Strategy Overview

Transport Philosophy

Abhavtech.com's SD-WAN transport strategy employs a multi-transport architecture that leverages diverse connectivity options to achieve optimal application performance, cost efficiency, and resilience. The design abstracts transport complexity while maintaining deterministic SLA delivery.

Transport Selection Criteria

Criterion Weight MPLS Internet LTE/5G Satellite
Reliability 25% 9/10 7/10 6/10 5/10
Latency 20% 9/10 7/10 6/10 3/10
Bandwidth Cost 20% 3/10 9/10 5/10 4/10
Availability 15% 8/10 8/10 7/10 9/10
Scalability 10% 5/10 9/10 8/10 6/10
Deployment Speed 10% 4/10 8/10 9/10 7/10
Weighted Score 100% 6.55 7.80 6.55 5.45

Strategic Transport Decision

                    TRANSPORT STRATEGY DECISION MATRIX
+==============================================================================+
|                                                                              |
|   CURRENT STATE                        TARGET STATE                          |
|   +------------------+                 +------------------+                  |
|   | MPLS Only        |    =======>    | Hybrid Transport |                  |
|   | $XX,XXX/month    |                | $XX,XXX/month    |                  |
|   | Single Provider  |                | Multi-Provider   |                  |
|   | Fixed Bandwidth  |                | Elastic Scale    |                  |
|   +------------------+                 +------------------+                  |
|                                                                              |
|   MIGRATION APPROACH: Phased Transport Addition                              |
|   +----------------------------------------------------------------------+  |
|   | Phase 1: Add Internet transport (DIA) to all sites                   |  |
|   | Phase 2: Add LTE/5G backup to branches                               |  |
|   | Phase 3: Reduce MPLS to hub-only (50% reduction)                     |  |
|   | Phase 4: Final MPLS optimization (retain critical paths only)        |  |
|   +----------------------------------------------------------------------+  |
|                                                                              |
+==============================================================================+

2.5.2 Transport Types and Characteristics

Primary Transport: MPLS (Retained for Critical Paths)

Parameter Hub Sites Branch Sites
Bandwidth 100-500 Mbps 50-100 Mbps
SLA Guarantee 99.99% 99.95%
Latency (intra-region) <10ms <15ms
Jitter <2ms <5ms
Packet Loss <0.1% <0.5%
QoS Classes 6 4
Cost per Mbps $XXX-XXX $XXX-XXX

MPLS Retention Strategy: - Mumbai DC ↔ Chennai DR: Retained (critical replication) - Hub-to-Hub interconnects: Evaluate based on traffic patterns - Branch sites: Migrate to Internet primary + LTE backup

Secondary Transport: Business Internet (DIA)

Site Provider Bandwidth Type SLA Monthly Cost
Mumbai DC Tata Communications 1 Gbps Dedicated 99.9% $X,XXX
Chennai DR Airtel 1 Gbps Dedicated 99.9% $X,XXX
London BT 500 Mbps DIA 99.9% $X,XXX
Frankfurt Deutsche Telekom 500 Mbps DIA 99.9% $X,XXX
New Jersey Verizon 500 Mbps DIA 99.9% $X,XXX
Dallas AT&T 500 Mbps DIA 99.9% $X,XXX
Bangalore Jio Fiber 200 Mbps Business 99.5% $XXX
Delhi Airtel 200 Mbps Business 99.5% $XXX
Noida Tata 100 Mbps Business 99.5% $XXX

Tertiary Transport: Cellular (LTE/5G)

Site Technology Provider Bandwidth Purpose
Mumbai DC 5G Jio Up to 1 Gbps Disaster backup
Chennai DR 5G Airtel Up to 500 Mbps Disaster backup
Bangalore 4G LTE Jio 100 Mbps Primary backup
Delhi 4G LTE Airtel 100 Mbps Primary backup
Noida 4G LTE Vodafone 50 Mbps Primary backup
London 5G EE 500 Mbps Disaster backup
Frankfurt 5G Vodafone DE 500 Mbps Disaster backup
New Jersey 5G Verizon 500 Mbps Disaster backup
Dallas 5G T-Mobile 500 Mbps Disaster backup

2.5.3 Transport Color Mapping

Color Assignment Strategy

                        SD-WAN TRANSPORT COLOR SCHEME
+==============================================================================+
|                                                                              |
|   COLOR           TRANSPORT TYPE          CHARACTERISTICS                    |
|   +----------+    +------------------+    +-----------------------------+    |
|   | mpls     | => | MPLS Private WAN | => | Low latency, guaranteed QoS |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
|   +----------+    +------------------+    +-----------------------------+    |
|   | biz-     | => | Business DIA     | => | Dedicated, SLA-backed       |    |
|   | internet |    | (Enterprise)     |    | Higher reliability          |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
|   +----------+    +------------------+    +-----------------------------+    |
|   | public-  | => | Public Internet  | => | Best effort, variable       |    |
|   | internet |    | (Commodity)      |    | Lower cost                  |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
|   +----------+    +------------------+    +-----------------------------+    |
|   | lte      | => | 4G LTE Cellular  | => | Wireless backup             |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
|   +----------+    +------------------+    +-----------------------------+    |
|   | 5g       | => | 5G Cellular      | => | High-speed wireless         |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
|   +----------+    +------------------+    +-----------------------------+    |
|   | private1 | => | Custom Private   | => | Reserved for expansion      |    |
|   +----------+    +------------------+    +-----------------------------+    |
|                                                                              |
+==============================================================================+

Site-Specific Color Configuration

Site Color 1 Color 2 Color 3 Notes
Mumbai DC mpls biz-internet 5g Triple transport
Chennai DR mpls biz-internet 5g Triple transport
London mpls biz-internet 5g Triple transport
Frankfurt mpls biz-internet 5g Triple transport
New Jersey mpls biz-internet 5g Triple transport
Dallas mpls biz-internet 5g Triple transport
Bangalore biz-internet lte - Dual transport
Delhi biz-internet lte - Dual transport
Noida biz-internet lte - Dual transport

2.5.4 Transport Interface Configuration

WAN Edge Interface Mapping

Hub Sites (C8300-2N2S-6T / C8500-12X4QC):

!======================================================================
! MUMBAI DC - C8500-12X4QC TRANSPORT INTERFACES
!======================================================================
!
! MPLS Transport (Color: mpls)
interface TenGigabitEthernet0/0/0
 description MPLS-PRIMARY-TATA-100G
 mtu 9216
 ip address 198.51.100.1 255.255.255.252
 negotiation auto
 sdwan
  tunnel-interface
   encapsulation ipsec weight 1
   color mpls
   max-control-connections 2
   no allow-service all
   allow-service bfd
   allow-service bgp
   allow-service dhcp
   allow-service dns
   allow-service icmp
   allow-service netconf
   allow-service ntp
   allow-service ospf
   allow-service sshd
   allow-service stun
!
! Business Internet Transport (Color: biz-internet)
interface TenGigabitEthernet0/0/1
 description DIA-PRIMARY-TATA-1G
 mtu 1500
 ip address 203.0.113.1 255.255.255.252
 ip nat outside
 negotiation auto
 sdwan
  tunnel-interface
   encapsulation ipsec weight 1
   color biz-internet
   carrier Tata-Communications
   max-control-connections 2
   vbond-as-stun-server
   no allow-service all
   allow-service bfd
   allow-service bgp
   allow-service dhcp
   allow-service dns
   allow-service icmp
   allow-service https
   allow-service netconf
   allow-service ntp
   allow-service sshd
   allow-service stun
!
! 5G Cellular Backup (Color: 5g)
interface Cellular0/4/0
 description 5G-BACKUP-JIO
 ip address negotiated
 ip nat outside
 dialer in-band
 dialer-group 1
 pulse-time 1
 sdwan
  tunnel-interface
   encapsulation ipsec weight 10
   color 5g
   carrier Jio-5G
   max-control-connections 1
   last-resort-circuit
   low-bandwidth-link
   vbond-as-stun-server
   no allow-service all
   allow-service bfd
   allow-service dhcp
   allow-service dns
   allow-service icmp
   allow-service stun

Branch Sites (C8200L-1N-4T):

!======================================================================
! BANGALORE BRANCH - C8200L-1N-4T TRANSPORT INTERFACES
!======================================================================
!
! Business Internet Primary (Color: biz-internet)
interface GigabitEthernet0/0/0
 description DIA-PRIMARY-JIO-200M
 mtu 1500
 ip address dhcp
 ip nat outside
 negotiation auto
 sdwan
  tunnel-interface
   encapsulation ipsec weight 1
   color biz-internet
   carrier Jio-Fiber
   max-control-connections 2
   vbond-as-stun-server
   no allow-service all
   allow-service bfd
   allow-service dhcp
   allow-service dns
   allow-service icmp
   allow-service https
   allow-service ntp
   allow-service sshd
   allow-service stun
!
! LTE Backup (Color: lte)
interface Cellular0/1/0
 description LTE-BACKUP-JIO
 ip address negotiated
 ip nat outside
 dialer in-band
 dialer-group 1
 pulse-time 1
 sdwan
  tunnel-interface
   encapsulation ipsec weight 5
   color lte
   carrier Jio-LTE
   max-control-connections 1
   last-resort-circuit
   low-bandwidth-link
   vbond-as-stun-server
   no allow-service all
   allow-service bfd
   allow-service dhcp
   allow-service dns
   allow-service icmp
   allow-service stun

2.5.5 NAT Traversal and Firewall Requirements

NAT Scenarios

Scenario Description Solution Notes
Public IP Direct routable address Direct tunnel MPLS, dedicated DIA
NAT44 Single NAT translation STUN Standard broadband
Double NAT CGN + local NAT STUN + vBond relay Cellular, some ISPs
Symmetric NAT Port-restricted vBond relay required Problematic ISPs

Firewall Port Requirements

Protocol Port Direction Purpose
DTLS UDP 12346 Outbound Control connections
TLS TCP 23456 Outbound Control connections (backup)
IPsec UDP 12346 Bidirectional Data plane tunnels
IPsec UDP 4500 Bidirectional NAT-T encapsulation
IKEv2 UDP 500 Bidirectional Key exchange
STUN UDP 3478 Outbound NAT traversal
NTP UDP 123 Outbound Time synchronization
DNS UDP/TCP 53 Outbound Name resolution
HTTPS TCP 443 Outbound Cloud services, software updates

NAT Configuration for Internet Transports

!======================================================================
! NAT CONFIGURATION FOR INTERNET TRANSPORTS
!======================================================================
!
! NAT Pool for Service VPNs
ip nat pool SDWAN-NAT 203.0.113.10 203.0.113.30 prefix-length 27
!
! Inside Interface Definition
interface GigabitEthernet0/0/1
 ip nat inside
!
! NAT Overload for Internet Access
ip nat inside source list NAT-ACL interface GigabitEthernet0/0/0 overload
!
! NAT ACL
ip access-list extended NAT-ACL
 10 permit ip 10.0.0.0 0.255.255.255 any
 20 permit ip 172.16.0.0 0.15.255.255 any
 30 permit ip 192.168.0.0 0.0.255.255 any
!
! TCP MSS Adjustment
ip tcp adjust-mss 1360

2.5.6 Transport SLA Definitions

SLA Threshold Configuration

SLA Class Latency Jitter Loss Application Type
Real-Time <150ms <30ms <1% Voice, Video
Business-Critical <200ms <50ms <2% SAP, Oracle, Citrix
Default <300ms <100ms <5% General business
Best-Effort No limit No limit No limit Bulk data, backup

Transport SLA Baseline per Site

Site Transport Expected Latency Expected Jitter Expected Loss
Mumbai DC MPLS 5ms 1ms 0.01%
Mumbai DC DIA 15ms 5ms 0.1%
Mumbai DC 5G 25ms 10ms 0.5%
Chennai DR MPLS 8ms 2ms 0.02%
Chennai DR DIA 18ms 6ms 0.15%
London MPLS 120ms (to India) 5ms 0.1%
London DIA 140ms (to India) 15ms 0.3%
Frankfurt MPLS 125ms (to India) 5ms 0.1%
New Jersey MPLS 180ms (to India) 8ms 0.15%
Dallas MPLS 200ms (to India) 10ms 0.2%
Bangalore DIA 20ms (to Mumbai) 8ms 0.2%
Delhi DIA 25ms (to Mumbai) 10ms 0.25%
Noida DIA 22ms (to Mumbai) 8ms 0.2%

2.5.7 Transport Redundancy Design

Redundancy Model

                    TRANSPORT REDUNDANCY ARCHITECTURE
+==============================================================================+
|                                                                              |
|   HUB SITES (Mumbai, Chennai, London, Frankfurt, NJ, Dallas)                |
|   +----------------------------------------------------------------------+  |
|   |                                                                      |  |
|   |   Transport 1: MPLS ─────────────────────> Primary (weight: 1)      |  |
|   |        │                                                             |  |
|   |        └── BFD: 1000ms hello, multiplier 3, 3-second detect         |  |
|   |                                                                      |  |
|   |   Transport 2: DIA ──────────────────────> Secondary (weight: 1)    |  |
|   |        │                                                             |  |
|   |        └── BFD: 1000ms hello, multiplier 3, 3-second detect         |  |
|   |                                                                      |  |
|   |   Transport 3: 5G ───────────────────────> Tertiary (weight: 10)    |  |
|   |        │              (last-resort-circuit)                          |  |
|   |        └── BFD: 1000ms hello, multiplier 7, 7-second detect         |  |
|   |                                                                      |  |
|   +----------------------------------------------------------------------+  |
|                                                                              |
|   BRANCH SITES (Bangalore, Delhi, Noida)                                    |
|   +----------------------------------------------------------------------+  |
|   |                                                                      |  |
|   |   Transport 1: DIA ──────────────────────> Primary (weight: 1)      |  |
|   |        │                                                             |  |
|   |        └── BFD: 1000ms hello, multiplier 3, 3-second detect         |  |
|   |                                                                      |  |
|   |   Transport 2: LTE ──────────────────────> Backup (weight: 5)       |  |
|   |        │              (last-resort-circuit)                          |  |
|   |        └── BFD: 1000ms hello, multiplier 7, 7-second detect         |  |
|   |                                                                      |  |
|   +----------------------------------------------------------------------+  |
|                                                                              |
+==============================================================================+

Failover Scenarios

Scenario Trigger Action Convergence Time
MPLS failure BFD timeout (3s) Shift to DIA <5 seconds
DIA failure BFD timeout (3s) Shift to MPLS/5G <5 seconds
Dual transport failure BFD timeout Activate LTE/5G <10 seconds
Complete site failure All BFD timeout Traffic via alternate site <15 seconds

2.5.8 Transport Cost Analysis

Monthly Transport Costs

Site MPLS DIA Cellular Total
Mumbai DC $XX,XXX $X,XXX $XXX $XX,XXX
Chennai DR $XX,XXX $X,XXX $XXX $XX,XXX
London $X,XXX $X,XXX $XXX $XX,XXX
Frankfurt $X,XXX $X,XXX $XXX $X,XXX
New Jersey $X,XXX $X,XXX $XXX $X,XXX
Dallas $X,XXX $X,XXX $XXX $X,XXX
Bangalore $X $XXX $XXX $XXX
Delhi $X $XXX $XXX $XXX
Noida $X $XXX $XX $XXX
Total $XX,XXX $XX,XXX $X,XXX $XX,XXX

Cost Comparison: Current vs. Target

Metric Current (MPLS Only) Target (Hybrid) Savings
Monthly Cost $XX,XXX $XX,XXX $XX,XXX (20%)
Annual Cost $XXX,XXX $XXX,XXX $XXX,XXX
3-Year TCO $X,XXX,XXX $X,XXX,XXX $XXX,XXX
Bandwidth (Aggregate) 2.5 Gbps 8.5 Gbps +240%
Cost per Mbps $XX.XX $X.XX -76%

2.5.9 Transport Verification Commands

Control Plane Verification

!======================================================================
! TRANSPORT CONTROL PLANE VERIFICATION
!======================================================================
!
! Verify TLOC registration
show sdwan control local-properties
!
! Expected Output:
! personality                       vedge
! sp-organization-name              ABHAVTECH-COM
! organization-name                 ABHAVTECH-COM
! root-ca-chain-status              Installed
! certificate-status                Installed
! dns-name                          vbond.abhavtech.com
! vBond                             True
! number-active-wan-interfaces      3
!
! Verify control connections
show sdwan control connections
!
! Expected Output:
! PEER     PEER    PEER            SITE      DOMAIN   PEER     PRIV     PEER      PUB     LOCAL   REMOTE  PEER     UPTIME
! TYPE     PROT    SYSTEM IP       ID        ID       PRIVATE  PORT     PUBLIC    PORT    COLOR   COLOR   STATE
! vsmart   dtls    10.255.255.1    100       1        192.168.1.1  12346  198.51.100.1  12346  mpls    default  up
! vsmart   dtls    10.255.255.2    100       1        192.168.1.2  12346  198.51.100.2  12346  mpls    default  up
! vmanage  dtls    10.255.254.1    100       0        192.168.1.10 12346  198.51.100.10 12346  mpls    default  up

Data Plane Verification

!======================================================================
! TRANSPORT DATA PLANE VERIFICATION
!======================================================================
!
! Verify BFD sessions
show sdwan bfd sessions
!
! Expected Output:
! SOURCE         DEST           SITE    DETECT   TX      COLOR     STATE   UPTIME
! TLOC           TLOC           ID      MULT     INTVL
! 10.1.100.1     10.1.200.1     200     7        1000    mpls      up      5:12:33:05
! 10.1.100.1     10.1.200.1     200     7        1000    biz-int   up      5:12:33:02
! 10.1.100.1     10.1.300.1     300     7        1000    mpls      up      5:12:32:58
!
! Verify tunnel statistics
show sdwan tunnel statistics
!
! Verify transport health
show sdwan app-route statistics
!
! Sample Output:
! app-route statistics 10.1.100.1 12346 10.1.200.1 12346 ipsec
!  remote-system-ip  10.1.200.1
!  local-color       mpls
!  remote-color      mpls
!  mean-latency      8
!  mean-jitter       2
!  mean-loss         0.00
!  average-latency   8
!  average-jitter    2
!  average-loss      0.00

2.5.10 Transport Best Practices

Design Recommendations

  1. Diverse Path Selection: Use different carriers for different transports to avoid common points of failure
  2. Color Consistency: Maintain consistent color assignment across all sites for policy predictability
  3. BFD Tuning: Adjust BFD timers based on transport characteristics (faster for dedicated, slower for cellular)
  4. Weight Assignment: Use weights to influence traffic distribution (lower weight = preferred path)
  5. Last Resort Circuits: Mark cellular/satellite as last-resort to prevent unnecessary usage
  6. MTU Management: Configure appropriate MTU per transport to avoid fragmentation
  7. NAT-T Enablement: Enable NAT traversal on all Internet-facing transports
  8. STUN Server: Use vBond as STUN server for NAT discovery

Operational Considerations

Area Recommendation Rationale
Monitoring Poll transport metrics every 60 seconds Balance visibility vs. overhead
Alerting Alert on BFD flaps > 3 per hour Identify unstable transports
Capacity Plan for 70% utilization threshold Allow headroom for bursts
Testing Monthly failover testing Validate redundancy works
Documentation Update transport inventory quarterly Track circuit changes

Document Control

Version Date Author Changes
1.0 December 30, 2025 Network Architecture Team Initial release

This document is part of the Abhavtech.com SD-WAN Documentation Suite Confidential - Internal Use Only