> For the complete documentation index, see [llms.txt](https://docs.console.zenlayer.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.console.zenlayer.com/welcome/ip-transit/high-availability/ha-faq.md).

# FAQ

**Do both ports need to be in the same city?**

Yes. The system validates this automatically during creation. The standby port dropdown only shows ports in the same city as the primary port; ports in other cities are grayed out and cannot be selected.

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**Can I delete just one link?**

No. Both links in an HA instance must be deleted together. Deleting individual links is not supported.

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**Does switching HA modes interrupt service?**

No. The change takes effect immediately without affecting service connectivity.

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**Can I upgrade an existing single-link instance to HA?**

Not in the current release. Support for upgrading existing single-link instances to HA is planned for a future version.

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**Can the two links have different bandwidth specs?**

No. When changing bandwidth on an HA instance, both links are updated to the same specification simultaneously.

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**What is the SLA for an HA instance?**

The dual-link HA architecture delivers an SLA of **99.95%**, higher than the single-link standard.

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**How is inbound traffic handled after a primary/standby switch?**

Inbound traffic must be redirected by the customer via BGP routing policy. The **Switch Primary Port** operation in zenConsole controls return (egress) traffic only.

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For further assistance, contact the Zenlayer technical support team.