DNS & Network Architecture¶
This chapter covers DNS configuration, network requirements, QoS policies, firewall rules, and edge architecture for Webex Calling and Contact Center.
Chapter Overview¶
Sections¶
5.1 DNS Configuration ->
Complete DNS and network architecture including DNS requirements, network bandwidth calculations, QoS policies, firewall rules, edge/zone architecture, and troubleshooting
5.2 Network Requirements ->
Bandwidth calculations per site, WAN optimization, SD-WAN integration, MPLS vs Internet transport
5.3 QoS & Bandwidth ->
Traffic marking (DSCP), queue prioritization, bandwidth reservation, WAN QoS policies
5.4 Firewall Rules ->
Required ports and protocols, IP address ranges, NAT configuration, security policies
5.5 Edge Architecture ->
Network edge design, public IP allocation, SIP ALG disable, session border controller requirements
5.6 Zone Configuration ->
Webex Zone deployment (India), Trusted Network Edge configuration, SIP trunk setup, trunk groups
5.7 Troubleshooting ->
Network connectivity tests, SIP trunk diagnostics, media path verification, latency/jitter analysis
Network Requirements Overview¶
Bandwidth per Site¶
| Site Type | Users | Calls (Busy Hour) | Bandwidth Required |
|---|---|---|---|
| Large Hub | 1,000+ | 200+ | 10 Mbps (signaling + media) |
| Regional Hub | 300-1,000 | 60-200 | 5 Mbps |
| Branch | <300 | <60 | 2 Mbps |
| Remote/WFH | Individual | 1-2 | 100 Kbps per user |
Port Requirements¶
| Service | Protocol | Ports | Direction |
|---|---|---|---|
| SIP Signaling | TCP/TLS | 5060-5061 | Outbound |
| Media (RTP) | UDP | 8000-12000 | Bidirectional |
| HTTPS (Control Hub) | TCP | 443 | Outbound |
| STUN/TURN | UDP | 3478 | Outbound |
DNS Configuration¶
Required DNS Records¶
Public DNS (External):
; Webex Calling - SIP Federation
_sipfederationtls._tcp.abhavtech.com. SRV 0 0 5061 sipdir.online.lync.com.
; Webex Meetings - Not part of this migration but often co-deployed
_sip._tls.abhavtech.com. SRV 0 0 443 sipdir.online.lync.com.
Internal DNS (Split-brain for on-premises devices):
QoS Policy¶
DSCP Marking¶
| Traffic Type | DSCP | CoS | Queue | Description |
|---|---|---|---|---|
| Voice (RTP) | EF (46) | 5 | Priority | Real-time voice media |
| SIP Signaling | CS3 (24) | 3 | Control | Call setup/teardown |
| Video | AF41 (34) | 4 | Real-time | Video conferencing |
| Best Effort | 0 | 0 | Default | All other traffic |
WAN QoS Configuration¶
! Priority Queue for Voice
policy-map WAN-OUT
class VOICE-MEDIA
priority percent 33
set dscp ef
class SIP-SIGNALING
bandwidth percent 5
set dscp cs3
class class-default
fair-queue
Firewall Configuration¶
Webex Calling IP Ranges¶
APAC (Mumbai + Chennai DCs): - Signaling: 202.177.192.0/19 - Media: 210.4.192.0/20
UK (London): - Signaling: 185.115.196.0/22 - Media: 62.109.192.0/18
EU (Frankfurt): - Signaling: 64.68.96.0/19 - Media: 170.133.128.0/18
Americas (US): - Signaling: 64.68.96.0/19 - Media: 170.133.128.0/18
Dynamic IP Ranges
Webex IP ranges are subject to change. Always verify current ranges at: https://help.webex.com/article/b2exve
Edge & Zone Architecture¶
India Zone Deployment¶
Required for: Geographic DIDs (toll bypass compliance)
+-------------------------------------------------------------+
| INDIA ZONE/EDGE ARCHITECTURE |
+-------------------------------------------------------------+
| |
| +--------------+ +--------------+ |
| | Webex Edge | | Local Gateway| |
| | (DMZ) |<-------------------->| (PSTN) | |
| +------+-------+ +------+-------+ |
| | | |
| | SIP Trunk | SIP Trunk |
| v v |
| +--------------+ +--------------+ |
| | Webex Zone | | Tata/Airtel | |
| | (Enterprise) | | SIP Trunks | |
| +--------------+ +--------------+ |
| |
+-------------------------------------------------------------+
Components: - Webex Zone: On-premises signaling gateway - Trusted Network Edge: Public IP for PSTN connectivity - Local Gateway: ISR 4K series router with CUBE
Network Validation¶
Before go-live:
- DNS records created and validated
- Bandwidth capacity confirmed per site
- QoS policies configured on WAN
- Firewall rules implemented
- Zone/Edge deployed (India sites)
- Network connectivity tests passed
Next Steps¶
- Review Implementation for deployment procedures
- Review Appendix F for DNS record templates
- Review Appendix G for firewall rule templates